Answer:
The correct answer is a) A tendency for consumers to buy more of a good when its price decreases and less when its price increases
Explanation:
A classical definition of the law of demand in microeconomics states that the the demand for a good rises when it's price is lowered, while the demand for a product decreases if the price increases - assuming all other factors are constant.
While pretty simple at it's core, the theory sets the basis for how a simple economic system works.
For corporations, the basic theory dictates how to price a product, how to increase sales and ensure better profits.
For government, it can show how the economic might stagnant if there is too much inflation.