—What do you think of being a volunteer, John?—I find it a stressful job but one you can

—What do you think of being a volunteer, John?
—I find it a stressful job but one you can really help people.
A. where
B. which
C. when
D. that

(答案→)A. whereB. whichC. whenD. that解析：考查定语从句。one指代job，即，先行词是job（工作），定语从句you can really help people不缺少成分，排除B、D；where指地点，也可指抽象的地点，当先行词是position，point，job等且从句不缺成分时，用where引导定语从句，意为“在（志愿者）这份工作中”。而when指时间，排除C。故选A。

我也是这个答案