Sentence Correction

By showing that South Africa does not have a free market and is in fact a kind of collectivist welfare state for Whites only, Sowell argues that American conservatives have no valid ideological grounds to be in sympathy with the Pretoria regime.
(A) to be in sympathy with
(B) to sympathize with
(C) for sympathizing with
(D) that they should sympathize with
(E) that they should have sympathy for


OA:C
IMO: B
SC 1000 Q190
Please explain thank

I believe "grounds for..." is idiomatic.

Ex: "Grounds for dismissal".

even i think its B
plz explain anyone??

Grounds for is the correct idiom

(C)

Correct idiom - grounds for...

Also, showing ---- sympathizing is correct here