My jaws would ( ) lock together tightly, or they would sudden

My jaws would ( ) lock together tightly, or they would suddenly become limp and fall loose.
A、neither
B、either
C、too
D、also
【正确答案】：B
【题目解析】：either…or… 要么…要么…,句子含义是我的下颚要么仅仅扣在一起，要么松垮垮地垂下。