For an amplifier characterized by the h-parameter equivalent circuit, the voltage gain is influenced by:

Correct option is D

​$$\text{For an amplifier modeled using the } h\text{-parameter equivalent circuit, the voltage gain depends on:} \\[8pt]\bullet \ h_{11} \rightarrow \text{ input impedance parameter} \\[4pt]\bullet \ h_{12} \rightarrow \text{ reverse voltage feedback parameter} \\[4pt]\bullet \ h_{21} \rightarrow \text{ forward current gain parameter} \\[4pt]\bullet \ h_{22} \rightarrow \text{ output admittance parameter} \\[8pt]\text{Along with the source and load resistances, all four } h\text{-parameters collectively influence the voltage gain.} \\[8pt]\text{Although in many practical low-frequency analyses } h_{12} \text{ and } h_{22} \text{ may be small and sometimes neglected, the complete and accurate expression for voltage gain includes all four } h\text{-parameters.}$$​​