Answer:
In
the
band.
Step-by-step explanation:
Prepositional phrases are described as the phrases that begins with a preposition followed by its object and any of the modifier preceding the object to modify it. These phrases primarily function as adjectival or adverbial phrases in order to modify the noun or verb and add detail to the sentence. In the given sentence, the preposition 'in', its object 'band', and modifier of the object 'the' comprise the prepositional phrase and functions as adjectival phrase to modify the noun 'musical instruments.'