A body of mass 10 kg is moving with a constant velocity of 10 m/s. When a constant force acts for 4 seconds on it, it moves with a velocity 2 m/sec in the opposite direction. The acceleration produced in it is [MP PET 1997]

• A.             \[3\,m/{{\sec }^{2}}\]          
• B.             \[-3m/{{\sec }^{2}}\]
• C.             \[0.3\,m/{{\sec }^{2}}\]       
• D.             \[-0.3\,m/{{\sec }^{2}}\]