Answer
$1.68\;\rm A$
Work Step by Step
We know that the current density is given by
$$J=\sigma E=\dfrac{I}{A}$$
So,
$$I=\sigma_{Al} E A$$
Plug the known; using Table 30.2
$$I=(3.5\times 10^7)(0.012)(4\times 10^{-6})$$
$$I=\color{red}{\bf 1.68}\;\rm A$$