Answer:
B. ![18x^{2} y^{2} \sqrt[3]{3xy^{2} }](https://tex.z-dn.net/?f=18x%5E%7B2%7D%20y%5E%7B2%7D%20%5Csqrt%5B3%5D%7B3xy%5E%7B2%7D%20%7D)
Step-by-step explanation:
To simplify this expression, use the fact that the root of a number (in this case is the cube root) can be expressed like a fractional exponent (1/3). Using this, the expression changes to:

Next step is to put the exponent inside the parenthesis:
Find the prime factorization of 648:
648 =3⋅3⋅3⋅3⋅2⋅2⋅2
648=3⁴∗2³

Change all improper fractions in exponent to mixed fractions

Separate integers exponents from fractional:

Re-arrange (all numbers with fractional exponents must be together):

Multiply the 3x with the numbers that have an integer exponent:

Take out the exponent 1/3 from the parenthesis:

And change the representation of the root to use a radical symbol
![18x^{2} y^{2} \sqrt[3]{3xy^{2} }](https://tex.z-dn.net/?f=18x%5E%7B2%7D%20y%5E%7B2%7D%20%5Csqrt%5B3%5D%7B3xy%5E%7B2%7D%20%7D)