36 Divided by 6 :]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]
21 is a rational number because it is an integer, which can be converted into a fraction.
<u>Step-by-step explanation:</u>
When a denominater and numerator are integers and gives a quotient then it is a rational number.
21/1, where 21 is denominator and 1 is numerator the quotient is 21. Therefore 21 is a rational number which can also be considered as a ratio.
The answer is the 3rd one