Answer:
The correct answer is option B. Gerund.
Explanation:
The gerund is a form of the verb that can act as a noun. The gerund is formed with the ending -ing.
In this case the gerund is located after a preposition, and one of the rules of grammar tells us that after a preposition we can only use the gerund, never an infinitive verb.
Other ways of use are:
- When one verb follows another verb.
- As a subject or complement of a sentence.
- After phrasal verbs.
