Which of the following is a determinant of the price elasticity of demand for a product?
I. The existence of substitute goods
II. The percentage of a consumer's total budget devoted to purchases of that commodity

The law of demand states that

a. there is a positive relationship between price and quantity demanded b. price is the only factor that influences the quantity that people are willing and able to buy c. price and quantity demanded are inversely related d. the demand curve shifts whenever the price of a good changes e. by producing a product, firms create a demand for it

A country is said to have a comparative advantage in a good over another country if that first country:

A. Can produce more units of the good B. Is a more efficient producer of the good C. Is a major consumer of the good D. Has a lower opportunity cost of producing the good