The 12-foot-long bed of a dump truck loaded with debris rises on the front end in order for the debris to spill out. If the front of the bed rises to a height of 6 ft., which equation can be used to determine the angle of elevation of the bed?

A. sin x = 12/6
B. tan x = 6/12
C. sin x = 6/12
D. cos x = 6/12