There exists diminishing _______________ for gambles

What does it mean when a good is rival in consumption?

a) One person's use of the good diminishes another person's ability to use it. b) People can be prevented from using the good. c) No more than one person can use the good at a time. d) Everyone will be excluded from obtaining the good.

Suppose that total sales in an industry in a particular year are $600 million and sales by the top four sellers are $200 million, $150 million, $100 million, and $50 million, respectively. We can conclude that:

A. price leadership exists in this industry. B. the concentration ratio is more than 80 percent. C. this industry is a differentiated oligopoly. D. the firms in this industry face a kinked demand curve.