Which sentence uses punctuation correctly? a. they want an apartment, that has space, and charm. b. they want an apartment, that has space and charm. c. they want an apartment that has space, and charm. d. they want an apartment that has space and charm.

The correct answer is D - They want an apartment that has space and charm. A and B are incorrect, because the comma is placed at the wrong spot. B would be correct if there were three items there, for example - They want an apartment that has space, charm, and light. Then it would be correct. This way, since there are only two items enumerated here, you don't have to use a comma there.