State which of the following situations are possible and give an example of each of these:
$(a)$ $A$ body moving with constant acceleration but with zero velocity.
$(b)$ $A$ body moving horizontally with an acceleration in the vertical direction.
$(c)$ $A$ body moving with a constant speed in an accelerated motion.

(A-D) Yes,this is possible at the highest point of a body thrown vertically upwards. At the highest point,the body's velocity is $0 \ m/s$,but it experiences a constant acceleration due to gravity of $9.8 \ m/s^2$ in the downward direction.
$(b)$ Yes,this is possible for a projectile. $A$ projectile fired at an angle has a constant horizontal velocity,but its motion along the vertical direction is subject to a constant downward acceleration due to gravity.
$(c)$ Yes,this is possible when a body moves along a circular path with constant speed. In this situation,the speed is constant,but because the direction of motion changes continuously,the body possesses centripetal acceleration.