Verified Answer :

I don't know the sentence... maybe you can post it in the comments?

Because from the options: all of them could be gerund! A gerund is a verb-form that can function as a noun; as a subject in the sentence. For example: ;
Driving is my favourite pastime.

so, chose the one that you can substitute (along with any words that come with it; such as "driving cars") with "it" and the sentence would still make sense,