In the sentence that sounds like a good idea the verb sounds is

The verb "sounds" in this sentence is a linking verb. This is so because the word connects the subject and in this sentence we have "that" as the subject to a noun or adjective that describes the subject. In our sentence above, the phrase "like a good idea" or "good idea" is an adjective that describes the subject. 

The correct answer is b

Iguess the answer is d