<prompt> Congenital mega colon is confirmed by:Rectal biopsySigmoidoscopyBarium enemaInvertogram  <response>: a. Rectal biopsyRef: Nelsons 20e p 1894-1897Ghai 8e p 285-286Congenital Aganglionic Megacolon is the other name for Hirschsprung diseaseDiagnosis of Hirschsprung disease is confirmed by rectal biopsy. 