Kelly simplified this power of a product

(7w⁻⁹)⁻³

1. 7⁻³. (w⁻⁹)⁻³

2. 1/343 w²⁷

Use Kelly's steps to simplify this expression

(5w⁷)²

What is the simplified power of the product?

A. 5w⁹

B. 10w¹⁴

C. 25w⁹

D. 25w¹⁴