For a given lift of the followers in a given angular motion of the cam, the acceleration/retardation of the follower will be the least when the profile of the cam during the rise portion is

(a) Such that the follower motion is simple harmonic

(b) Such that the follower motion has a constant velocity from start to end

(c) A straight line, it being a tangent cam

(d) Such that the follower velocity increases linearly for half the rise portion and then decrease linearly for the remaining half of the rise portion.