Answer
$3.2\;\rm mA$
Work Step by Step
We know that the current is given by
$$I=\dfrac{Q}{t}$$
where $Q=Ne$ where $N$ is the number of electrons and $e$ is the charge of one electron.
$$I=\dfrac{Ne}{t}$$
Plug the known;
$$I=\dfrac{(2\times 10^{13})(1.6\times 10^{-19})}{(1\times 10^{-3})}$$
$$I=\bf 0.0032\;\rm A=\color{red}{\bf 3.2}\;\rm mA$$
