Which of the following defines the market demand curve? a. A market demand curve shows the total quantity demanded of a good per period by all consumers at various prices. b. A market demand curve shows the total quantity demanded per period by all consumers having the same income. c. A market demand curve shows the total quantity demanded over a period of time by all consumers at various prices. d. A market demand curve shows the total quantity demanded of various goods by an individual consumer at various prices. Utility definitions Dmitri is arguing with his girlfriend, Frances. They have been going out for a little more than two years. FRANCES: I'm leaving you, Dmitri. Get over it. DMITRI: Are you saying that being single will make you happier than you've been with me? Speaking personally, I think the utility we've had in this relationship was much more than you could have had if you'd been single this whole time! FRANCES: I had taken an economics class and the word "utility" rings a bell. It's not that at all. We've had a fine time. It's that the utility I would get by continuing our relationship isn't worth it anymore