B. A Blocks A and B, of masses m, mp, are at rest on a frictionless surface, as shown above, with block A fixed to the table. Block C of mass me is suspended by a string that is tied to block B over an ideal pulley. Which of the following gives the magnitude of the force exerted by block A on block B ?

B. A Blocks A and B, of masses m, mp, are at rest on a frictionless surface, as shown above, with block A fixed to the table. Block C of mass me is suspended by a string that is tied to block B over an ideal pulley. Which of the following gives the magnitude of the force exerted by block A on block B ?