Correct Answer - Option 4 : Degree of reaction
Degree of reaction in axial flow compressor
\(\begin{array}{l}
= \frac{{Pressure\;Rise\;in\;rotor}}{{Pressure\;Rise\;in\;stage}}\\
= \frac{{Static\;enthalpy\;rise\;in\;rotor}}{{Static\;enthalpy\;rise\;in\;stage}}
\end{array}\)