Answer:
The correct pronoun used is 'our'.
Finding the lost child was a matter of our duty, not heroism.
Explanation:
A pronoun is the part of speech which is used in the place of a noun. It is used as a substitution for a noun in a sentence. The use of the pronouns helps in non-repetition of the noun in a sentence. In the above sentence, the pronoun 'our' will be used. The use of the pronoun depends upon the agreement of it with the antecedent.
