"My sister needs a pretty office."

Shouldn't "Mi hermana necesita un despacho bonito" be accepted?

Can someone explain why XCM17 answer is not correct . Is it because the subject is female?

This is the answer Duo gave me "Mi hermana necesita un bufete bonito".

Now it gave me this option ??Mi hermana precisa un bufete bonito.

it should be "mi hermana necesita un bonito oficina