Which factor caused various cities to conduct strikes in 1919? a- racial violence b- seasonal trial c- anarchist bombings d- demobilization

The answer you are looking for is D demobilization i hope it helps:)

A war consisting of fighting on two separate sides.

Example:

During World War One, the German Empire had two fight the British & French on the Western Front. They also had to fight the Russians and Serbians on the Eastern Front. Germany was in a Two front war with fighting on the West and East of their nation.