Rachel spends her entire daily income on pizza, at $2 per slice, and cookies, at $1 per cookie. For the current mix of pizza and cookies in her bundle, Rachel's marginal utility for pizza is 20 and her marginal utility for cookies is 15. What should Rachel do to maximize her utility?

Nothing -- This bundle already maximizes her utility

A .Buy more pizza and fewer cookies, until the marginal utility of both goods is equal

B. Buy more cookies and less pizza, until the marginal utility of both goods is equal

C. Buy more cookies and less pizza, until the marginal utility per dollar is equal for both goods

D. Buy more pizza and fewer cookies, until the marginal utility per dollar is equal for both goods