D. Somewhere under the couch cushions is the remote control. This sentence has the verb agree with its subject.
A sentence must have a subject, a verb, and must express a complete thought. The order of the subject and a verb is not fixed. A subject usually comes before the verb or vice versa. In the above sentences, the verb comes before the subject.
To avoid confusion and really identify the correct subject-verb agreement. We must rearrange the sentences. For example:
Choice D can be rearranged into:
The remote control is somewhere under the couch cushions.
Subject: remote control - singular
Verb: is - singular