First option because 3 x 10^9 is 3,000,000,000
If I'm correct and the ^ stands for multiplication then the answer should be 5.
The picture is my work just ignore the fraction.
Answer:
3^12
Step-by-step explanation:
When multiplying the same number with different exponents you have to add the the exponents. For example:

So (3^6)(3)(3^5) or (3^6)(3^1)(3^5) = 3^(6+1+5) = 3^12