The square root of a number is a number, that when multiplied by itself equals the number in the square root.
SQRT(144) = 12, (12*12=144) 12 is a whole number.
SQRT(156) = 12.49 , Not a whole number.
SQRT(169) = 13, is a whole number.
SQRT(196) = 14, is a whole number.
The answer would be B.