I believe that it is D, so sorry if it's wrong, I haven't done this in a while.
1. You need to multiply the denominator by something that will make the content of the radical be a square—so that when you take the square root, you get something rational. Easiest and best is to multiply by √6. Of course, you must multiply the numerator by the same thing. Then simplify.

2. Identify the squares under the radical and remove them.

Answer:
There is no next step, the problem is answered!
Step-by-step explanation: