Block B, with mass 5.00 kg, rests on block A, with mass 8.00 kg, which in turn

Question:

Block B, with mass 5.00 kg, rests on block A, with mass 8.00 kg, which in turn is on a horizontal tabletop (Fig. 5.72). There is no friction between block A and the tabletop, but the coefficient of static friction between block A and block B is 0.750. A light string attached to block A passes over a frictionless, mass less pulley, and block C is suspended from the other end of the string. What is the largest mass that block C can have so that blocks A and B still slide together when 1he system is released from rest?

B A