Which of these operations is not closed for polynomials?

A. Multiplication

B. Addition

C. Division

The answer is C. Division.

Addition and subtraction are closed for polynomials because the result of adding or multiplying two polynomials is always another polynomial.

Division on the other hand is not closed for polynomials; if you divide two polynomials the result is not always a polynomial.

Therefore, we can conclude that the correct answer is C.