You obtain a batch of poly$($hexamethylene adipamide$)($nylon $6,6)$ that has a degree of polymerization of

What is its number$-$average molecular weight?

$56578\frac{g}{m}ol$

$28290\frac{g}{m}ol$

$79613\frac{g}{m}ol$

$113\frac{g}{m}ol$

$226\frac{g}{m}ol$

$318\frac{g}{m}ol$