Question

Why is the bold pronoun used correctly in the sentence below?

It is important for us choir members to take individual responsibility for learning our parts.

It is a possessive.
It is the object of the preposition for.
It is the subject of the sentence.
It is the objective form of we.

Answer 1

U did not provide the sentence but it found it as shown below:
"It is important for us choir members to take individual responsibility for learning our part."
Well, assuming that the italicized pronoun is the word 'us' , the answer is : E. it is the objective form of we

Since it acted as an object, it needed to be change into the objective form. 'It is important for we . . .' will not work since we is a subjective pronoun

hope this helps