Write the correct alternative answer for each of the following questions.

Which of the following is a polynomial?

Option (A) is not a polynomial. Hence, incorrect option.

(B) is x^√2 – 3x is not a polynomial because it does not have natural number power. Hence, incorrect.

(C) x^-2 + 7 is not a polynomial. Because it has negative power. Hence, incorrect.

(D) is the quadratic polynomial.

The option D is the only valid polynomial because in this polynomial only the power of the variable is a whole number.