The output of the following circuit is equivalent to $.......$ gate

Current $I$ through a given $p-n$ junction when a voltage $V$ is applied across it is given to be $I=I_0\left(e^{\frac{V}{2 V_T}}-1\right)$, where $I_0$ and $V_T$ are constants. If $r_d(I)$ is the dynamic resistance of the junction, then $r_d\left(1000 I_0\right)=\alpha r_d\left(10 I_0\right)$, where $\alpha$ is approximately equal to

For an $n-p-n$ transistor structure, which of the following statements is not true?

The behaviour of the circuit is like $\_\_\_\_$ gate