"`sqrt(6-4sqrt(3)+sqrt(16-8sqrt(3)))` is equal to `1-sqrt(3)` b. `sqrt(3)-1` c. `2(2-sqrt(3))`

"`sqrt(6-4sqrt(3)+sqrt(16-8sqrt(3)))` is equal to `1-sqrt(3)` b. `sqrt(3)-1` c. `2(2-sqrt(3))` d. `2(2+sqrt(3))`"