It was interesting to go through all the answers. I hope to
make the analysis of these answers more interesting:
1. Everybody has stated that ans#1 is wrong. Ofcourse it is
wrong but not completely. In the very beginning this was
tried and was not found to be suitable.
2. Ans2 and 3 are correct and it is to be added that VSB is
just a TYPE of AM and an ingenious method to reduce the
band width by around 40%.
3. AM for video and FM for audio but what for color? In
fact an entirely new type of AM is used for this and not
only this; two signals are nodulated on one carrier and
the carrier is not sent!
Interesting or confusing; reck the brain