Specify which of the two variables is the independent variable and which is the dependent variable.

a.	The quantity of CDs purchased is reduced due to a drop in the price of digitally streamed music.
b.	A reduction in Canadian household incomes leads to the government spending more on transfer payments to households.
c.	The number of people seeking a career in computer programming expands due to a rise in the average salary of computer programmers.
d.	A fall in the price of wheat fertilizer increases the amount of wheat planted by farmers.
e.	Canada's rate of economic growth drops because of a fall in output per worker in the Canadian economy.