语法问题

14. During the examination we were supposed to stay in our seats, keep our eyes on our work, ________ to anyone.
A. but could not talk
B. rather than speak
C. instead of speaking
D. and not speak
此题答案错误 正确答案为: D 新东方在线相关课程
为什么是D。。。
我放A。
这是我从『基础英语』那里做的测试。