To help is which type of verb

The phrase to help is an example of an infinitive verb. An infinitive is formed by using the word to followed by the base form of the verb such as to eat to write or to help. Infinitives can function as nouns adjectives or adverbs within a sentence. They are very flexible and used widely in English grammar. Participles are used to show tense or form adjectives while gerunds are ing forms used as nouns. Modals are auxiliary verbs that show possibility necessity or permission. Therefore to help is correctly classified as an infinitive making option B the right answer.