Answer
$d^{6}$ would be the simplest form.
Work Step by Step
The quotient has powers with the same base in the numerator and denominator.
The property of dividing powers with the same base applies.
Thus, $\displaystyle \frac{d^{7}}{d}=\frac{d^{7}}{d^{1}}=d^{7-1}=d^{6}$
$d^{6}$ would be the simplest form.
