${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}(1-t)e^{32t-16t^2}dt$

Describe the most appropriate substitution case and the values $ofu$ and $du.$ Select the correct choice below and fill $in$ the answer boxes within your choice.

$A.$ Substitute $u$ for the quantity $in$ the denominator. Let $u=so$ that $du=dt.$

$B.$ Substitute $u$ for the exponent $one.$ Let $u=,so$ that $du=()dt.$

$C.$ Substitute $u$ for the quantity under a root $or$ raised $to$ a power. Let $u=so$ that $du=()dt$