The change in availability of the system is

Question

For a steady flow process from state 1 to 2, enthalpy changes from h₁ = 400 kJ/kg to h₂ = 100 kJ/kg and entropy changes from s₁ = 1.1 kJ/kg-K to s₂ = 0.7 kJ/kg-K. Surrounding environmental temperatue is 300 K Neglect changes in kinetic and potential energy. The change in availability of the system is            

(a) 420 kJ/kg               (b) 300 kJ/kg

(c) 180 kJ/kg               (d) 90 kJ/kg