17. Haley Megan Fosnough-Biersmith goes shopping for shoes and has plenty of money with her. She will keep buying shoes until (LO2) a) her total utility equals the price b) her marginal utility equals the price c) she runs out of money d) the store runs out of shoes 18. Colin Kelley maximizes his utility when -. (LO4) a) the marginal utility of everything he buys is equal to its price b) the marginal utility of everything he buys is zero c) he no longer enjoys a consumer surplus d) he buys only the lowest-priced goods and services