Answer:
B. 5^6 x 3^12
Explanation:
(5^2 x 3^4)^3 = 
5 x 5 x 3 x 3 x 3 x 3 =
25 x 81 = 
2025 
2025^3 =
8,303,765,625
Option B is correct because,
5^6 x 3^12 =
5 x 5 x 5 x 5 x 5 x 5 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3 =
15,625 x 531,441 = 
8,303,765,625