If $R_C$ and $R_B$ are respectively the resistances of in collector and base sides of the circuit, and…
If $R_C$ and $R_B$ are respectively the resistances of in collector and base sides of the circuit, and $\beta$ is the current amplification factor, then the voltage gain of a transistor amplifier in common emitter configuration is
$\beta R_C R_B$
$\frac{\beta}{R_C R_B}$
$\frac{\beta R_B}{R_C}$
$\frac{\beta R_C}{R_B}$
Solution
The voltage gain of a CE configuration transistor is
$A_V=\frac{V_O}{V_I}=\frac{V_C}{V_B}=\frac{I_C R_C}{I_B R_B}=\left(\frac{I_C}{I_B}\right)\left(\frac{R_C}{R_B}\right)=\beta \cdot \frac{R_C}{R_B}$