Which sentence does not contain any errors in comma usage?

a.
it is, a hexagonal, traffic sign.

b.
jeremy has an old red wagon.

c.
the antique, and enormous clock stands in our living room.

d.
the stereo was designed with four, large speakers.

This question is obviously focused on commas, so if you say these sentences out loud and use breaks after every comma, you can tell which sentence doesn't make sense. So the answer is (d.).

i think that it is letter d.

a. she is a young, beautiful woman who deeply cares about her husband.

is correct