One kg of air (R=287 J/kg-K) goes through an irreversible process between two equilibrium state 1 ($$30^\circ C$$, 1.2 m$$^3$$) and state 2 ($$30^\circ C$$, 0.8 m$$^3$$). What is the change in entropy (in J/kg-K)?

A

-116.36

B

-50.53

C

50.53

D

116.36