Determine all critical points for the following function.

$f(x)=x(8-x{)}^3$

What is the derivative of $f(x)=x(8-x{)}^3?$

$f^{\text{'}}(x)=$

$$

Find the critical points, if any, of $f$ on the domain. Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

A$.$ The critical point$($s$)$ occur$($s$)$ at $x=$

$($Use a comma to separate answers as needed.$)$

B$.$ There are no critical points for $f(x)=x(8-x{)}^3$ on the domain.