A ball is dropped on the floor from a height of 10 m. It rebounds to a height of 2.5 m. If the ball is in contact with the floor for 0.01 sec, the average acceleration during contact is [BHU 1997; CPMT 1997]

• A.             2100\[m/{{\sec }^{2}}\]downwards
• B.             2100\[m/{{\sec }^{2}}\]upwards
• C.             1400\[m/{{\sec }^{2}}\]      
• D.             700\[m/{{\sec }^{2}}\]