单选题 The writer ______ the newspaper readers against buying shares without getting good advice first.
【正确答案】 C
【答案解析】caution sb. against sth．警告或劝告某人防止做某事；spur鞭策，刺激，疾驰，驱策；menace恐吓，威胁；induce劝诱，促使，导致。