What is the source of the supply of dollars in the market for foreign-currency exchange?

With respect to monopolistic competition,

a. both the business-stealing externality and the product-variety externality are positive externalities. b. the business-stealing externality is a positive externality, while the product-variety externality is a negative externality. c. the business-stealing externality is a negative externality, while the product-variety externality is a positive externality. d. both the business-stealing externality and the product-variety externality are negative externalities.

Suppose at the consumer's current consumption bundle the marginal rate of substitution of cheese for wine is 1/2 bottle of wine per pound of cheese. The price of one pound of cheese is $6, and the price of a bottle of wine is $10 . The consumer should increase his consumption of

a. cheese, decrease his consumption of wine, and move to a lower indifference curve. b. cheese, decrease his consumption of wine, and move to a higher indifference curve. c. wine, decrease consumption of cheese, and move to a higher indifference curve. d. cheese, decrease consumption of wine, and remain on the same indifference curve.