What is the enthalpy change of 15oC system if the heat capacity of air at 20oC is 10 J/oC and heat capacity of water vapor at 20oC is 20 J/oC, enthalpy of vaporization is 20 J, and the humidity is 50%?

• A. t50 J
• B. t60 J
• C. t80 J
• D. t110 J