Guys lemme explain this modifier bit a little further.
Consider this statement :
when discussing the greatest rivalry, < what goes here ???> <-- a gmat rule about modifiers is that the object of the verb in the first sentence goes here. So what goes there is the person who's doing the discussing.
For instance :
When discussing the greatest rivalry, George Bush said <blah blah> < --- correct
when discussing the greatest rivalry, two horses <-- I dont know the last time I saw two horses discuss something
This is why I feel that A, B, C,E are all incorrect. Any thoughts ?
Racing fans often debate which was the finest thoroughbred racehorse, but,
when discussing the greatest rivalry, the horses Affirmed and Alydar are consistently at the top of everyone's list.
A.when discussing the greatest rivalry
B.when discussing which rivalry is the greatest
C.while discussing the greatest rivalry
D.whenever the greatest rivalry is discussedE.if discussing the greatest rivalry