The two sentences that use an apostrophe correctly in a plural possessive noun are:
- The United States’ national anthem is “The Star-Spangled Banner.”
- The basketball players’ lockers will be cleaned out on Friday.
In the first sentence, "United States’" shows possession for the national anthem belonging to the United States, which is considered a singular entity despite its plural form. In the second sentence, "players’" indicates that the lockers belong to multiple basketball players.