Which sentence shows correct use of the plural genitive case?

The sentence "The boys' team won." correctly utilizes the plural genitive case, which indicates possession by multiple subjects. In this case, the term "boys'" shows that the team belongs to more than one boy. The apostrophe after "boys" signifies that it is plural possessive.

This construction is vital in English grammar, particularly in establishing relationships where ownership or association is highlighted. The singular possessive form would use "boy's" with an apostrophe before the "s," indicating ownership by one boy, while "boys'" implies that the team is collectively associated with multiple boys.

The other options either misuse apostrophes or do not denote ownership appropriately, failing to express the intended meaning of possession correctly.