What is the average drift speed of conduction electrons in a copper wire of cross-sectional area $1.0\times {10}^{-7} {\mathrm{m}}^2$ carrying a current of 1.5 A? Assume that each copper atom contributes roughly one conduction electron. The density of copper is $9.0\times {10}^3 \mathrm{kg}/{\mathrm{m}}^3,$ and its atomic mass is 63.5 u. 

$1. 1.1 \mathrm{mm} {\mathrm{s}}^{-1}$
$2. 2.1 \mathrm{mm} {\mathrm{s}}^{-1}$
$3. 3.1 \mathrm{mm} {\mathrm{s}}^{-1}$
$4. 4.1 \mathrm{mm} {\mathrm{s}}^{-1}$

Which one of the following is correct?