Which of the following best explains why Economists and Marxists have a difficult time understanding each other? a) Marxists believe in a workers revolution while economists believe in promoting commerce. b) Economists believe private property and self interest are important and can serve society well, while Marxists support collective ownership of property and want to supplant self-interest with the common societal welfare. c) For economists the Exchange Theory of Value, which states that the value of something is in what people are willing to give up for it, is a fundamental concept in economic theory. Marxists reject this theory in favor of the older Labor Theory of Value, which claims the source of value for something is in the labor that went into producing it. And the two theories are incompatible. d) Marxists believe workers are always exploited by employers and the employment contract is always unfair, while economists believe that a market determined wage is fair.