D.
This is because:
8/8 rounds up to a whole number and 12/9 and 3/2 are improper fractions as the numerator (top number) is more than the denominator (bottom number)
To estimate a square root, find the two perfect squares the number is closest to, then continue with further decimals, i.e. if the question is square root of 5, it is between 4 and 9. As such, the answer is between 2 and 3. Alternatively, use a calculator for a quick estimation of many decimal points.
