Answer: OPTION B
Step-by-step explanation:
You need to remember that, to subtract radicals, the indices and the radicands must be the same.
Given the expression
, you can identify that both have index 2 and the radicands are 2 (The numbers that are inside of radicals), therefore, you can conclude that the subtraction can be made.
Then, you must subtract the terms in front of the radicals. Therefore, you get:

You can observe that this matches with the option B.