The correct option is C 9x3
A polynomial expression which contains only one term is called a monomial.
A polynomial whose degree is equal to 3 is called a cubic polynomial.
4x3+2x+6
is a cubic trinomial as its degree is 3 and it has 3 terms.
x+5
is a linear binomial as its degree is 1 and it has 2 terms.
9x3
is a cubic monomial as its degree is 3 and it has only one term.
2x2+2x+7
is a quadratic trinomial as its degree is 2 and it has 3 terms.