ANSWER
[tex]18 {m}^{2} {n}^{2} [/tex]
EXPLANATION
A monomial is a simplified polynomial with only one term.
The given expression is
[tex]18 {m}^{2} {n}^{2} [/tex]
This is an algebraic expression in m and n.
The 18 is a constant.
The 18 is the coefficient.
The degree is the sum of the exponents of the variable which is 2+2=4
We cannot simplify this polynomial further and it has only one term.
Therefore
[tex]18 {m}^{2} {n}^{2} [/tex]
is a monomial.
