Label each of the following scenarios with the correct combination of price change and quantity change. In some scenarios, it may not be possible from the information given to determine the direction of a particular price change or a particular quantity change. We will symbolize those cases as, respectively, "P?" and "Q?".

a. On a hot day, both demand for lemonade and supply of lemonade increase.

b. On a cold day, both demand for ice cream and the supply of ice cream decrease.

c. When Hawaii's Mt. Kilauea erupts violently, the demand on the part of tourists for sightseeing flights increases but the supply of pilots willing to provide these dangerous flights decreases.

d. In a hot area of Arizona where they generate a lot of their electricity with wind turbines, the demand for electricity falls on windy days as people switch off their air conditioners and enjoy the breeze. But at the same time, the amount of electricity supplied increases as the wind turbines spin faster.