So for this, you will be doing two different multiplications: 3 x 4 and √8 x √3.
3 x 4 = 12
√8 x √3 = √24
Now our result is 12√24, however, this can be simplified. Using the product rule of radicals (√ab = √a x √b), our simplification is such:
12√24 = 12√(8 x 3) = 12√(4 x 2 x 3) = 2 x 12√(2 x 3) = 24√6
In short, the answer is 24√6, or the first option.