Answer:

Explanation:
Here let us first write our expression
It says, x raise to 4 5th power i.e 4 by 5 , again raise to 3 7th power i.e 3 by 7
or

Now in this we apply the rule of product of exponents . The rule is like this.

Let us apply the rule in our problem



Which is x to the 12 over 35 hence our b option is correct