Which is true?
a. a change in quantity demanded is a response to a price change and a change in demand is a response to a non-price change
b. a change in demand and a change in quantity demanded both happen in response to price changes
c. both describe a movement along a single demand curve
d. the two terms can be used interchangeably
e. a change in quantity demanded occurs when price increases and a change in demand occur when a price decreases

The correct answer is option A.

Explanation:

A change in quantity demanded occurs because of a change in the price of the product. It is indicated by a movement on the same demand curve. There is an inverse relationship between quantity demanded and price of a product while other factors remain constant. So when price increases, the quantity demanded falls and vice versa.

A change in demand occurs because of a change in other factors while the price of the product remains constant. This is indicated by a shift in the demand curve. The other factors are the price of other goods, tastes, and preferences, the income of the consumer, etc.

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