A worker on a scaffolding 75 ft above the ground needs to lift a 500 lb bucket of cement from the ground to a point 30 ft above the ground by pulling on a rope weighing 0.5 lb/ft. Choose the integral needed to calculate how much work is required? A. 30 (500+ 0.5h) dh B. 30 (500+ (37.5-0.5h)) dh c. (500+ (37.5-0.5h)) dh D. 75 (500+ 0.5h) dh OA OB oc OD