High pressure steam is expanded adiabati-cally and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ΔH and ΔS respectively for this process:

Answer: Option B

For a reversible adiabatic process the entropy change is zero since $$dS=\frac{\delta Q}{T}$$
But the enthalpy change need not be zero since the internal energy and pressure energy may vary during the process.