The sentence with correct pronoun-antecedent agreement is:
A. Lucy decided to stop babysitting for the Garzas because their two boys would not stop hitting each other with foam bats.
In this sentence, "their" correctly refers to "the Garzas."
The other sentences have issues with pronoun-antecedent agreement:
- In B, "each other" would be better suited as "one another" since it refers to a group (the members of the soccer team) interacting.
- In C, "one another" is more appropriate than "each other" when referring to more than two people, and "they" refers to both Betty and Hilary, which could be misleading in terms of splitting time.
- In D, the pronoun "their" could lead to confusion since "her editors" is singular while "their staff" is plural, leading to potential antecedent disagreement.
So, A is indeed the sentence with the correct agreement.