As both his parents are _______, he has to earn some money by delivering newspapers to pay for his education.
A.at workB.out of workC.in workD.working在线课程B
解析：
本题考查work构成短语的不同含义。根据左栏的辨异，结合本题主句的句意“他不得不通过送报纸来挣一点钱付学费”，从句中应表示“他父母失业”。