Sentence Correction

2. 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
My answer: B
OA: C

I got it wrong too. Searched in google and found this below expln,

'Grounds for sympathizing with' and not 'Grounds to sympathize with'

Example-

...Grounds for his suspension...
..Grounds to his suspension...

grounds for is the correct idiom eliminate A and B

D and E are wordier