The ancient village, ______ they visited during a recent trip, is the only tourist attraction ______ is well protected without any damage.

A．which, which

B．which, that

C．where, that

D．that, which

养鸡业在玉林市发展迅速，有力地推动玉林经济发展．在适宜的环境条件下养鸡场中人工孵化的有些鸡卵不能孵化出小鸡，最主要的原因是（　　）

A．鸡卵发育不完全

B．鸡卵中缺少营养物质

C．鸡卵没有受精

D．鸡卵没有胚盘