The work done in reversible polytropic steady flow processes is given by

(a) \(\frac{P_{1} V_{1}-P_{2} V_{2}}{n-1}\)

(b) \(\frac{n\left(P_{1} V_{1}-P_{2} V_{2}\right)}{n-1}\)

(c) \(n\left(P_{1} V_{1}-P_{2} V_{2}\right)\)

(d) \(\frac{n\left(P_{1} V_{1}-P_{2} V_{2}\right)}{n+1}\)