###Answer the question from the input provided. Please answer from input only.

###Input: A wide selection of serials are available from BBC Video on DVD, on sale in the United Kingdom, Australia, Canada and the United States. Every fully extant serial has been released on VHS, and BBC Worldwide continues to regularly release serials on DVD. The 2005 series is also available in its entirety on UMD for the PlayStation Portable. Eight original series serials have been released on Laserdisc and many have also been released on Betamax tape and Video 2000. One episode of Doctor Who (The Infinite Quest) was released on VCD. Only the series from 2009 onwards are available on Blu-ray, except for the 1970 story Spearhead from Space, released in July 2013. Many early releases have been re-released as special editions, with more bonus features.

Doctor Who has appeared on stage numerous times. In the early 1970s, Trevor Martin played the role in Doctor Who and the Daleks in the Seven Keys to Doomsday. In the late 1980s, Jon Pertwee and Colin Baker both played the Doctor at different times during the run of a play titled Doctor Who – The Ultimate Adventure. For two performances, while Pertwee was ill, David Banks (better known for playing Cybermen) played the Doctor. Other original plays have been staged as amateur productions, with other actors playing the Doctor, while Terry Nation wrote The Curse of the Daleks, a stage play mounted in the late 1960s, but without the Doctor.

Following the success of the 2005 series produced by Russell T Davies, the BBC commissioned Davies to produce a 13-part spin-off series titled Torchwood (an anagram of "Doctor Who"), set in modern-day Cardiff and investigating alien activities and crime. The series debuted on BBC Three on 22 October 2006. John Barrowman reprised his role of Jack Harkness from the 2005 series of Doctor Who. Two other actresses who appeared in Doctor Who also star in the series; Eve Myles as Gwen Cooper, who also played the similarly named servant girl Gwyneth in the 2005 Doctor Who episode "The Unquiet Dead", and Naoko Mori who reprised her role as Toshiko Sato first seen in "Aliens of London". A second series of Torchwood aired in 2008; for three episodes, the cast was joined by Freema Agyeman reprising her Doctor Who role of Martha Jones. A third series was broadcast from 6 to 10 July 2009, and consisted of a single five-part story called Children of Earth which was set largely in London. A fourth series, Torchwood: Miracle Day jointly produced by BBC Wales, BBC Worldwide and the American entertainment company Starz debuted in 2011. The series was predominantly set in the United States, though Wales remained part of the show's setting.

The Sarah Jane Adventures, starring Elisabeth Sladen who reprised her role as investigative journalist Sarah Jane Smith, was developed by CBBC; a special aired on New Year's Day 2007 and a full series began on 24 September 2007. A second series followed in 2008, notable for (as noted above) featuring the return of Brigadier Lethbridge-Stewart. A third in 2009 featured a crossover appearance from the main show by David Tennant as the Tenth Doctor. In 2010, a further such appearance featured Matt Smith as the Eleventh Doctor alongside former companion actress Katy Manning reprising her role as Jo Grant. A final, three-story fifth series was transmitted in autumn 2011 – uncompleted due to the death of Elisabeth Sladen in early 2011.

In 1993, for the franchise's 30th anniversary, another charity special, titled Dimensions in Time was produced for Children in Need, featuring all of the surviving actors who played the Doctor and a number of previous companions. It also featured a crossover with the soap opera EastEnders, the action taking place in the latter's Albert Square location and around Greenwich. The special was one of several special 3D programmes the BBC produced at the time, using a 3D system that made use of the Pulfrich effect requiring glasses with one darkened lens; the picture would look normal to those viewers who watched without the glasses.



###Question: What countries are the Doctor Who DVDs available to purchase?

###Answer: {'answer':'the United Kingdom, Australia, Canada and the United States'}