You have stopped for a train at a railroad crossing that is marked with a crossbuck sign. when the train has passed

I believe the answer is: You must not proceed until you are sure there are no other trains approaching on any of the tracks.

Crossbuck signs is put to indicates that there could be more than one train that can pass within a short time period. The maximum number of train could be up to 3 , so you need to make sure that there are no other trains approaching to avoid collisions.

answer; /// i believe that the correct answer is (a) making presentations;

answer; overt behavior;