The sentence with correct pronoun and antecedent agreement is:
While the neighbors were walking to the store, they dropped their money and the wind blew it away.
In this sentence, the pronoun "they" correctly refers to the plural antecedent "the neighbors," and "their" correctly refers back to "the neighbors" as well.
In the other sentences:
- In the first set, both sentences are identical and correct with "it" referring to the weather and "she" relating to Carol.
- In the second set, "he" incorrectly refers back to "the brothers," which is plural. It should be "they" to match the plural antecedent.
- In the last sentence, "she" does not agree with the plural antecedent "the teachers." It should be "they" to match the plural antecedent.