I think the answer is hello perfect took me ages to work out
The sentence that the verb agrees with the subject is, option A. Island of the Dolphins is based on a true story. The subject of the sentence is "Island of the Dolpins" and the verb used is "is". A singular form of the verb is used because the subject is in a singular form too. The subject described by the verb is a title of a Novel.
Answer:
Since no one is here yet, let’s wait till they arrive.
