Answer:
The answers are letters C and D.
Explanation:
In order to determine the answer, we have to know about monomials.
A monomial is an expression that has just one term. A term can be a variable with a coefficient or just a coefficient. It does not matter the grade of the variable, because the definition of monomial is related to the term.
According to the possible options:
A. There are two terms, so it is a binomial.
B. There are two terms, so it is a binomial.
C. There is just one term, so it is a monomial.
D. There is just one term, so it is a monomial.
Finally, the correct answers are letters C and D.