单选题 These are students who, at some stage of their undergraduate careers have class, either ______, or because they are asked to do so.

【正确答案】 A

【答案解析】[解析] 本题考查词义辨析。句意为：这些学生在他们的本科生涯中需要上课，无论是自愿的还是因为他们被要求这样做。A：自动地，以自由意志；B：有选择地；C：强制地，强迫地，必须地；D：必要地，必定地，必然地。分析句意可知，本题选A。