The law of comparative advantage explains which of the following?

Suppose you have $400,000 saved up and purchase a medium-sized house for $200,000. Consider the following 2 scenarios:

i. The very next day, the prices of all houses, including the one you have just bought, double. ii. The very next day, the prices of all houses, including the one you bought, fall by half. Show that both scenarios increase your utility.

The term "unit elasticity" is used to describe a situation in which a rise in price is accompanied by

a. a fall in total expenditure. b. a rise in total expenditure. c. constant total expenditure. d. a unit decrease in total expenditure.