Answer
$1.5\;\rm \mu J$
Work Step by Step
The work done by the charge escalator to move a charge is given by
$$W=\Delta U$$
where $\Delta U=q\Delta V$
$$W=q\Delta V=q(V_f-V_i)$$
Plug the known;
$$W= (1.0\times 10^{-6})(1.5-0)$$
$$W=\color{red}{\bf 1.5}\;\rm \mu J$$
