The sum of the prime factors of  $$9^6×12^4×7^7$$​ is:

Correct option is D

Given:

The number = $$9^6×12^4×7^7$$

Solution:

9 = $$3^2$$

​​$$9^6=(3^2)^6=3^{12}$$

12 =  $$2^2 \times3$$

​​$$12^4=(2^2×3)^4$$ = $$2^8 \times3^4$$

​$$7^7$$ = $$7^7$$

​​Combine like terms;

​$$3^{12+4}×2^8×7^7$$ 

​$$3^{16}×2^8×7^7$$

​​Sum of the prime factors:

3 + 2 + 7 = 12

Therefore, the sum of the prime factors is 12.

Thus, correct answer is (d) 12