Block A, with Mass M_A, Is Initially at Rest on a Horizontal

Block A, with mass m_A, is initially at rest on a horizontal floor.Block B, with mass m_B, is initially at rest on the horizontal top surface of A.The coefficient of static friction between the two blocks is $\mu$ $\mu$ _s.Block A is pulled with a horizontal force.It begins to slide out from under B if the force is greater than:

A) "m_Ag"
B) "m_Bg"
C) "m_Ag"
D) "11ef006a_bab8_2b86_bc85_c37bdd1a4142_TB6585_11m_Bg"
E) "11ef006a_bab8_2b86_bc85_c37bdd1a4142_TB6585_11
( m_A + m_B) g"