A bipolar transistor is operating in the active region with a collector current of $1 \mathrm{~mA}$. Assuming that the $\beta$ of the transistor is $100$ and the thermal voltage $\left(\mathrm{V}_{\mathrm{T}}\right)$ is $25 \; \mathrm{mV}$, the transconductance $\left(g_{m}\right)$ and the input resistance $\left(r_{n}\right)$ of the transistor in the common emitter configuration, are
- $g_{m}=25 \mathrm{~mA} / \mathrm{V}$ and $r_{n}=15.625 \; \mathrm{k} \Omega$
- $g_{\mathrm{m}}=40 \mathrm{~mA} / \mathrm{V}$ and $r_{n}=4.0 \; \mathrm{k}\Omega$
- $g_{m}=25 \mathrm{~mA} / \mathrm{V}$ and $r_{n}=2.5 \; \mathrm{k} \Omega$
- $g_{m}=40 \mathrm{~mA} / \mathrm{V}$ and $r_{n}=2.5 \; \mathrm{k} \Omega$