Which was a difficulty the builders of the transcontinental railroad had to overcome? a. meeting the demands of skilled union workers b. providing supplies to build tracks and support workers c. bridging the grand canyon and rio grande river d. building on the wet, marshy soil of the great plains

B. providing supplies to build tracks and support workers

Explanation:

Builders faces a series of difficulties during the construction of the Transcontinental railroad, one of them was getting supplies to the place they were building it, the supplies got there by ship and it took a long time.

a case involving the laws of a single state.