Which voice is equivalent to the expression below? ?
3√3+√6+√12-2√3
a. 2√3-√21
b. 5√3-6
c. 3√3+√6
d. 5√3

3√3+√6+√12-2√3

Can be even further simplified like this:
3√3+√2√3+√4√3-2√3
3√3+√6+2√3-2√3 (if you look here, the last 2 negates each other)
3√3+√6
Which makes it equal to option C.

Option C is the correct answer.