Hello, so the verb is the action and the compound subject is going to be
our second subject in the sentence. To distinguish whether it is
corresponding or not we are going to make sure that it is in the right tense, person, etc. So lets look at our options Our
first sentence has the first subject plural but not the second subject,
and an improper use of the verb making this sentence grammatically incorrect. Our second sentence the verb and compound correspond correctly so no mistakes here. The third sentence we are distinguishing whether we use begun or began. Began is past tense and begun is past participle. The last sentence is grammatically incorrect because the action/verb 'stores' does not correspond with our compound subject. So that leaves us with the answer being B. I hope I helped! If you have any other questions or would like further explanation please let me know! :)