The free energy of a system containing an interface of area 5mm2 and free energy 6 KJ/mol*mm2 per unit area is given by_______(G = 10 KJ/mol, is the free energy of the system assuming that all material in the system has the properties of the bulk).

• A. 40 KJ/mol
• B. 50 KJ/mol
• C. 20 KJ/mol
• D. 10 KJ/mol