The pipefitting subcontractor is required to lay pipe in a trench that is 10 ft deep and 3 ft wide with vertical walls and no sloping or other protection. The trench was dug by the excavator. The general contractor supervised the work but had no employees in the trench. The concrete subcontractor told the general contractor and excavator that the trench needed to be sloped or shored before their employees could work in the trench. During the OSHA inspection, OSHA observed the general contractor at the trench supervising the pipefitter in the trench. Which contractor(s) would receive a citation for an unsafe trench?
a. pipefitting only
b. pipefitting and excavator
c. pipefitting, excavator, and general contractor
d. pipefitting, excavator, general contractor, and concrete subcontractor