请找出下列各项中加点字注音完全正确的一项（     ）（2分）

A．绮丽(qǐ)伫立(chù)扶掖(yè)戛然而止(jiá)

B．庇(bì)护悄(qiǎo)然骸(hái)骨怏怏(yàng)不乐

C．休憩（qì）慰藉(jiè)咫尺（zhǐ）怒不可遏（é）

D．驯良（xùn）粗犷（guǎng）炮制（pào）锲而不舍（qiè）

Some students even have no idea of          they are studying, so they waste much time playing.

A．what

B．when

C．why

D．where