Explanation:
about gerund don't confuse your mind
it's just verb +ing
running
walking
talking
eating
reading
I’m sorry I don’t understand this question
"Please talk quietly in the library."
Imperative because it gives a command or request.
Hope I was able to help! :)
To my mind, the answer ( B ) is the inappropriate sentence. In a formal writing informal tone must be avoided as well as colloquial expressions.
