Answer:
The correct answer is: "To play the piano" . Here is used as a noun.
Explanation:
Infinitive phrases are those phrases that begin, as the name implies, with an infinitive (to + verb in the simple form).
As we can see in this case: "To play the piano".
The function of the infinitive phrases can be: adjectives, nouns or adverbs.
As a noun, its function is like the subject of the sentence.
