Suppose that John has been offered a job in New York City at a salary of $100,000 per year. Currently, John lives and works in the Midwest at a salary of $70,000 per year. As you know, NYC's cost of living is more than the Midwest. What type of costs should John consider in making his decision? Which would be "sunk" costs? "opportunity" costs? differential costs? Are there other qualitative factors that John might consider