On the floor of an elevator, a block of mass 50 kg is placed on which another block of mass 20 kg is also placed. The elevator is moving up with a constant acceleration 1.5 m/s². Force exerted by 20 kg block on the 50 kg block is nearly:

• A

  250 N

• B

  230 N

• C

  170 N

• D

  150 N