We could not reason out the way the robbers escaped because we were unable to find any of

问题补充：

We could not reason out the way the robbers escaped，because we were unable to find any of them.

A. chance

B. trace

C. point

D. signal

答案：

A. chance

(答案→)B. trace

C. point

D. signal

解析：句意：我们推断不出强盗是怎么逃走的，因为我们找不到他们的任何踪迹。trace“踪迹，痕迹，迹象”，符合句意。