Evaluations for input

Refrigerant-134a is expanded adiabatically from 100 psia and 100°F to a saturated vapor at 10 psia. Determine the entropy generation for this process, in Btu/lbm⋅R.<image 1>

(A) $0.00147\frac{Btu}{lbm\cdotR}$

(B) $0.00047\frac{Btu}{lbm\cdotR}$

(C) $0.00247\frac{Btu}{lbm\cdotR}$

Answer with the option's letter from the given choices directly. No punctuation.