For this question, we need to divide (6 x 10^8)/(3 x 10^6). In order to do so, we must divide the normal numbers and subtract the exponents. This then gives us 2 x 10^2, or 2 x 100. Since 2 x 100 is 200, the answer is B, 6 x 10^8 is 200 times larger than 3 x 10^6.
Hope this helps!