Identify the underlined phrase in the sentence. Henry's desire *to win* is obvious.

A. prepositional
B. participal
C. gerund
D. infinitive

D. infinitive

D. infinitive

To identify the underlined phrase in the sentence, we need to understand what each of the options represents.

A prepositional phrase is a group of words that begins with a preposition (e.g., in, on, at) and functions as an adjective or adverb in a sentence. In this sentence, "to win" is not functioning as a prepositional phrase because it does not start with a preposition.

A participial phrase is a group of words that includes a present or past participle and any modifiers or objects. In this sentence, there is no present or past participle, so "to win" does not qualify as a participial phrase.

A gerund phrase is a group of words that begins with a gerund (a verb form ending in -ing that functions as a noun). In this sentence, "to win" is not a gerund phrase because "win" is an infinitive, not a gerund.

An infinitive phrase is a group of words that begins with an infinitive (the base form of the verb preceded by "to") and includes any modifiers or objects. In this sentence, "to win" is an infinitive phrase because "to" precedes the base form of the verb "win."

Therefore, the correct answer is D. infinitive.