Which sentence has an unclear or missing pronoun antecedent?
a.
henry paid for his movie ticket entirely with quarters.
b.
the twins have made plans for their birthday party this weekend.
c.
after talking to my friends, i realized it was not something i would enjoy.
d.
my mother lost one of her earrings down the drain

the correct answer is the following.

one of the groups i belong to is the boy scouts. this is a problem-solving group because it has tasks that we need to solve in order to other people in different activities such as the rescue of lost pets, or elder people in need.

the other group i belong to is kids pro environment, and is an information-sharing group that tries to create conscience about the risks and problems that generate pollution in our cities. we share information to other students and parents on the importance of keep our communities clean and our skies clear.