Assume that the price for the services of tarot card readers has risen and sales of these services have fallen. This means that some event has caused the equilibrium price to rise and the equilibrium quantity to fall. Which of the following events could have caused? this?
A. The number of tarot card readers has decreased.
B. Tarot card readers are deliberately charging high prices thereby losing customers.
C. This is an example of the violation of the law of supply.
D. The demand for tarot card readers has decreased.