Which of the following descriptions best depicts the substitution effect?

a. the change in consumption resulting from a change in the consumer's income, holding the prices of the goods constant
b. the change in consumption resulting from a change in the consumer's income, holding the consumer's level of satisfaction constant
c. the change in consumption resulting from a change in the price of one good, holding the consumer's level of satisfaction constant
d. the change in consumption resulting from a change in the price of one good, allowing the consumer's level of satisfaction to change

c