You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
IPod

Context:
Some independent stereo manufacturers including JVC, Pioneer, Kenwood, Alpine, Sony, and Harman Kardon also have iPod-specific integration solutions. Alternative connection methods include adapter kits (that use the cassette deck or the CD changer port), audio input jacks, and FM transmitters such as the iTrip—although personal FM transmitters are illegal in some countries. Many car manufacturers have added audio input jacks as standard.

Question:
What has become a standard inclusion in cars for several different auto companies?

audio input jacks