Which expressions are polynomials

A) 20x^2

B) 20x^2/y

C) 20x^2+y^1/2

The answer is the option A: A) 20x^2

The explanation is shown below:

1. The polynomials can't have:

- Fractional exponents.

- Variables in the denominator.

2. As you can see, the option B) 20x^2/y has the variable "y" in the denominator, Therefore, it is not a polynomial.

3. The option C) 20x^2+y^1/2 has a fractional exponent, so it is not a polynomial.