单选题 The problem has been ______ my mind all day.
A. preying on B. getting at C. taking on D. seeing to

【正确答案】 A
【答案解析】prey on折磨，损害。句意：我整天在苦苦思索这一问题。get at到达，意指，攻击； take on承担(责任)，呈现(面貌)；see to负责，注意。