Answer:
I believe the answer is d
Step-by-step explanation:
A rational number is a number that can be written as a ratio. That means it can be written as a fraction, in which both the numerator (the number on top) and the denominator (the number on the bottom) are whole numbers.
In this case, since [tex]\sqrt{81}[/tex] can be simplified to 9 and 9 can be written as a fraction (9/1) it is a rational number.
