Answer
$1.4mC$
Work Step by Step
We can find the maximum charge as follows:
$Q_{max}=k\epsilon_{\circ}AE_{max}$
We plug in the known values to obtain:
$Q_{max}=(5.4)(8.8r\times 10^{-12})(0.0300)(10.0)(1.00\times 10^8)$
$Q_{max}=1.4\times 10^{-3}=1.4mC$