You were supposed to stay in you

You were supposed to stay in your seats, keep your eyes on your work，_________ to anyone.
A、but could not talk
B、could not talk
C、and not to speak
D、but not speak
【正确答案】：C
【题目解析】：本题考查平行结构。根据本句句意：你应该待在你的位子上，眼睛看着自己的作品，不要和任何人说话。所以应该用and表示stay, keep和speak的并列关系。排除AD。而B选项没有连词，所以也不对。排除法只能选C。但本人认为选项C也有问题，把该选项中的to去掉，才能符合平行结构特点。