Question

Which algebraic expression is a polynomial?

Answer 1

I can't find the exact answer choices, but consider the definition of polynomial: a mathematical expression consisting of variables, exponents, and operators, in which:
1. all exponents are non-negative integers.
2. variables are not contained within radicals
3. no variable appears in a denominator

so, with that in mind, go through the choices and see which choice fulfills these conditions

reference: https://www.mathsisfun.com/definitions/polynomial.html