D. 49 is equal to 7 times 7
A square root is basically the opposite of a square. When you square something, you multiply that number by itself. Such as 25 being 5^2 since 5*5=25.
So when you square root, you find the number that multiplied by itself to get that number. For example, the square root of 36 is 6 since 6*6=36.