When a customer chooses to accept an item of value from a business because it requires no incremental spending on the part of the customer, the customer is demonstrating the principle that: a. markets are an efficient way to organize economic activity. b. specialization produces benefits for society. c. customers are smarter than businesses. d. rational people think at the margin.

The correct answer is letter "B": rational people think at the margin.

Explanation:

The "rational people think at the margin" principle means that consumers consider the marginal benefits and costs of acquiring a good or service before the purchase is made. Purchases typically take place when the marginal benefit is higher than the marginal cost.

convection currents in magma drive plate tectonics. the answer is true.

answer: 11/12

step-by-step explanation: 4 1/4 and 3 1/3 is equivalent to 4 3/12 and 3 4/12. 4 3/12 - 3 4/12 =11/12