In the circuit below, assume that the long channel $\text{NMOS}$ transistor is biased in saturation. The small signal trans-conductance of the transistor is $g_{m}$. Neglect body effect, channel length modulation and intrinsic device capacitances. The small signal input impedance $Z_{i n}(j \omega)$ is $\_\_\_\_\_\_$
- $\frac{-g_{m}}{C_{1} C_{L} \omega^{2}}+\frac{1}{j \omega C_{1}}+\frac{1}{j \omega C_{L}}$
- $\frac{g_{m}}{C_{1} C_{L} \omega^{2}}+\frac{1}{j \omega C_{1}}+\frac{1}{j \omega C_{L}}$
- $\frac{1}{j \omega C_{1}}+\frac{1}{j \omega C_{L}}$
- $\frac{-g_{m}}{C_{1} C_{L} \omega^{2}}+\frac{1}{j \omega C_{1}+j \omega C_{L}}$