What is the minimum time ?

A rectangle ABCD of length 4 meters and width 3 meters [AB=4m , BC=3m] , a body started moving from rest from point A towards point C directly , it moves with a uniform acceleration = 5 m/s^2 until it reaches half the path then it continued to point C by uniform velocity . What is the best path the body must take to reach point D in the least time from the following ?

I. The body must move from C to D by uniform velocity.

II. The body must move from C to B by a uniform velocity then from B to D by acceleration =20 m/s^2

III. The body must move from C to B by acceleration = 10 m/s^2 then from B to D by uniform velocity