Because of the heavy traffic it was already time for lunch break she got to her office.A.

问题补充：

Because of the heavy traffic, it was already time for lunch break she got to her office.

A. since

B. that

C. when

D. until

答案：

A. since

B. that

(答案→)C. when

D. until

解析：根据题意可以判断是，因为交通很拥挤，等她到达办公室时已经是午饭空了。