Part A:
The best description of the author's perspective on the argument that "people are helpless in the face of sugar" is:
A. She believes people are not helpless and will change their behavior as they learn more about the risks of soda.
Part B:
The most relevant evidence in support of her perspective is:
C. Soda consumption is already slipping nationwide.
This quotation suggests that people are changing their behavior regarding soda consumption, aligning with the author's belief that individuals can make informed choices when aware of the risks.