Mary once taught English in a remote village school as a volunteer which is only on foot

问题补充：

Mary once taught English in a remote village school as a volunteer, which is only on foot.

A. acceptable

B. accessible

C. available

D. appropriate

答案：

A. acceptable

(答案→)B. accessible

C. available

D. appropriate

解析：B 连词形容词。句意：玛丽曾经在一所偏远的农场学校做志愿者教英语，那所学校只能步行到达。根据句意可知accessible表示可到达的，可进入的。符合语境。