Solid A, with Mass M, Is at Its Melting Point

Multiple Choice

Solid A, with mass M, is at its melting point T_A.It is placed in thermal contact with solid B, with heat capacity C_B and initially at temperature T_B (T_B > T_A) .The combination is thermally isolated.A has latent heat of fusion L and when it has melted has heat capacity C_A.If A completely melts the final temperature of both A and B is:

A) (C_AT_A + C_BT_B - ML) /(C_A + C_B)
B) (C_AT_A - C_BT_B + ML) /(C_A + C_B)
C) (C_AT_A - C_BT_B - ML) /(C_A + C_B)
D) (C_AT_A + C_BT_B + ML) /(C_A - C_B)