Which statement best demonstrates why the following is a non-example of a polynomial?

the quantity 33 over 16 minus the quantity 62 times y squared times x times y minus the quantity 35 times z to the power of 1 over 3 times y squared

a. The expression has a variable raised to a negative exponent.
b. The expression has a variable in the denominator of a fraction.
c. The expression has a negative coefficient.
d. The expression has a variable raised to a fraction.