Which of the following is not a video file extension?
A. avi
B. wav
C. mpegD. mov

A video file format/extension is a type of file format for storing digital video data on a computer system. Some of the video file extensions are:
MP4 (mp4, m4a, m4v, f4v, f4a, m4b, m4r, f4b, mov)
3GP (3gp, 3gp2, 3g2, 3gpp, 3gpp2)
OGG (ogg, oga, ogv, ogx)
WMV (wmv, wma, asf*)
WEBM (webm)
FLV (flv)
AVI
QuickTime