Answer:
C. infinitive
Explanation:
-Infinitive is created with two words to + verb and it doesn't function as a verb. Instead, it acts as a noun, adjective, or adverb.
-Gerund is a verb that ends with -ing and has the function of a noun.
-Infinitive phrase is a sentence that has an infinitive
-Gerund phrase is a sentence that has a gerund and works as a noun.
According to this, the answer is that the form of a verb that comes after the word to and acts as a noun, an adjective, or an adverb is infinitive.
