The question for how many "x" real numbers we can take its square, x², and it will end up in a prime less than 10.
By difinition, a prime number is a natural number greater than 1 that has only two factors: 1 and itself.
If we take a square of a number, it will already have at least the factors 1, itself (x²), and x, so it won't be prime.
So, there is no real number that with we take its square it will end up in a prime number.
Answer is A.
