Plzzzz help i will mark Brainlest And hurry i'm on a time limit

Ben simplified this expression.

(StartFraction 2 x Superscript negative 4 Baseline y Superscript 7 Baseline Over 3 x cubed y squared EndFraction) cubed

1. (StartFraction 2 y Superscript 5 Baseline Over 3 x Superscript 7 Baseline EndFraction) cubed

2. StartFraction 2 y Superscript 15 Baseline Over 3 x Superscript 21 Baseline EndFraction

Analyze Ben’s work. Did he simplify the expression correctly? If not, what was his mistake?

A:Yes, he is correct.

B:No, he needed to add the exponents of powers of the same base in the first step.

C:No, he needed to apply the exponent to all factors in the product in the second step.

D:No, he needed to simplify further by subtracting the exponents of the powers.