Answer:
B. 20x⁹
Step-by-step explanation:
A monomial is a polynomial with just one term.
Example: 3x²
A. 11x - 9
INCORRECT, this has two terms 11x and 9
B. 20x⁹
CORRECT, this only has one term!
C. 20x⁹ - 7x
INCORRECT, this has two terms 20x⁹ and 7x
D.9/x
INCORRECT, this is not a polynomial
Learn more about Polynomial here: https://brainly.com/question/12099138
