Final answer:
The subject 'Some of the cookies from the jar' requires a plural verb 'are' to make subject and verb agree.
Step-by-step explanation:
The correct answer is B. Some of the cookies from the jar are missing!
In this sentence, the subject is 'some of the cookies from the jar' which is a plural noun phrase. Therefore, it requires a plural verb 'are' to agree with it grammatically.
For compound subjects connected by 'and', we use a plural verb. In this case, 'some of the cookies' is the subject and it is a compound subject that requires a plural verb 'are'.