To convert the rational expression to the radical form we can remember the exponent property
A good way to memorize that is think about the square root, the square root in rational form is 1/2
In a general way, the number at the numerator will go INSIDE the root, and the number at the denominator will go OUTSIDE the root.
Using this rule, m^(2/3) will be
And we can see that it's letter A.
Therefore, the answer is Letter A!