Which sentence uses a verb that agrees with its subject? a. on the tops of many city buildings hides falcons' nests. b. under the ocean floor is many valuable minerals. c. there sit an extremely tired athlete. d. here are some new stamps from the post office.

The sentence that uses a verb that agrees with its subject is D. Here are some new stamps from the post office.

Subject - Stamps (plural) Verb - are (plural)

A) Subject - Buildings(plural) Verb used - hides (singular) should be: hide (plural)
B) Subject - Minerals (plural) Verb used - is (singular) should be: are (plural)
C) Subject - Athlete (singular) Verb used - sit (plural) should be: sits (singular)