Answer: a and d
Explanation:
First of all, we need to make a analysis of each letters:
a. factoring 32 = 2.2.2.2.2 =


then,
16 =

but

in conclusion that, this inequality is correct
b. 27 =

this first situation is equal to

the second situation is:
81 =

and

it's a mistake.
c. factoring 9:

<

it's wrong.
d. factoring 8 =

factoring 32 =

>

This is true.
Finally.. our correct answers is a and d.