Why the answer is "band"? The same meaning with ring?

English Language Tests, Intermediate level

ESL/EFL Test #838 [color=blue]“Real Life: Marriage (1)”, question 10

Before the wedding, James bought Monica an engagement ring. Then, prior to the wedding day, James bought a gold wedding for his bride. He will also wear this kind of ring, once they are officially married, to symbolize his love and commitment to his wife.

(a) bomb
(b) plant
© song
(d) band

English Language Tests, Intermediate level

ESL/EFL Test #838 [color=blue]“Real Life: Marriage (1)”, answer 10

Before the wedding, James bought Monica an engagement ring. Then, prior to the wedding day, James bought a gold wedding band for his bride. He will also wear this kind of ring, once they are officially married, to symbolize his love and commitment to his wife.

Correct answer: (d) band
[size=200]_________________________[/size]

Why the answer is “band”? The same meaning with ring?
thanks.

A wedding band is a type of ring.