A person pushes a heavy crate of mass m up a frictionless incline at an angle θ above the horizontal. The crate's speed v₀ is constant. How much work does the person do on the crate if they push the crate up a distance d from the base of the incline (as measured along the incline)? a. mgd b. mgdsin(θ) c. mgdcos(θ) d. mgdtan(θ)