Suppose almond milk and oat milk are a pair of substitutes. If the price of almond milk goes up, which statement is correct about the changes in the market for oat milk?

a.The equilibrium price will decrease and the equilibrium quantity will increase.

b.The equilibrium price will increase and the equilibrium quantity will decrease.

c.The equilibrium price and quantity will increase.

d.The equilibrium price and quantity will decrease.

Suppose that a pizza store sells pizza and French fries, and their opportunity costs are constant. Assume now that one of the ovens broke and the amount of pizza which can be produced per hour decreased. In this case, the opportunity cost of French fries

a.Increases.

b.Can either increase or decrease (need more information).

c.Decreases.

d.Does not change.