My father never approved _____ a foreigner.
a. her to marry
b. her marrying
c. she marrying
d. she not marry
Please answer the question with an explanation.
Either a or b work grammatically, but b is the most idiomatic and seems correct:
My father never approved her marrying a foreigner.
"Her marrying" is the action of her getting married. It is this that the father did not approve of.
Although "My father never approved her to marry a foreigner" makes grammatical sense, it sounds like the father had to give some kind of formal approval for his daughter to marry a foreigner, which is clearly not the case if she married a foreigner anyway.
To be really fussy, I would prefer if it said "my father never approved of her marrying a foreigner", but evidently that is not an option for you.