A 2 kg block is placed over a 4 kg block and both are placed on a smooth horizontal surface. The coefficient of friction between the blocks is 0.20. If a horizontal force of 12N is applied to the upper block, then which of the below statement is true. (Assume, g = 10 m/s). (a) both the blocks have same acceleration of 4 m/s (b) both the blocks have same acceleration of 2 m/s (c) upper block acceleration = 4 m/s, lower block acceleration = 1 m/s (d) upper block acceleration 1 m/s, lower block acceleration = 4 m/s =