For this case we have by definition that a monomial is the product of a known number (called coefficient) by one or several unknown values, represented by letters (literal part or variables).
If there were a sum or subtraction, it would be a binomial.
Examples of monomial:
![5x ^ 7 * y ^ 2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/k2b1honnr5empw6pdhdzd2rb45ubg1ylqh.png)
Then, according to the above, the correct option is option C.
Answer:
Option C