A horizontal force F pushes a 4 kg block (A) which pushes against a 2 kg block (B) as shown. The blocks have an acceleration of 3m/s² to the right. There is no friction between the blocks and the surfaces on which they slide. What is the net force B exerts on A?

• A

  6 N to the right

• B

  12 N to the right

• C

  6 N to the left

• D

  12 N to the left