Mr. Hanson's insistence that the bee hive be removed from his car convinced the mechanic to call an expert.
Insistence is the only option that fit in the blank since it is the only adjective of the list.
Insistence can fe defined as the fact or quality of insisting that something is the case or should be done.
Insistent is an adjective and insists is a verb. Insistency is not correct. So, those thre options could never complete the sentence.
