20. If this year's Nobel Prize winner in physics gives a free lecture at your school and just eight people attend, you may conclude that (LO1) a) no one derived any utility from his lecture b) none of the people who attended would have come if there had been an admission fee c) the lecture must have been at an inconvenient time. d) at least some of the people who attended enjoyed a consumer surplus. 21. Which statement would be true about a person who goes to an all-you-can-eat restaurant? (LO2) d) a) She will never eat more food than she would at a regular restaurant. b) She will eat until closing time. c) She will eat until the marginal utility of the last portion of food is zero. d) She will keep eating while her marginal utility is rising