Change in demand and change in quantity demanded are not the same because

Explanation

This question is asking about the difference between change in demand and change in quantity demanded. These two terms may sound similar, but they have different meanings. Change in demand refers to a shift in the entire demand curve, while change in quantity demanded refers to a movement along the demand curve.

Option A states that all factors affecting change in demand also affect change in quantity demanded except income. This is incorrect because changes in factors such as taste, price of substitutes or complements, and future expectations can cause a shift in demand, but won't necessarily affect the quantity demanded.

Option B says that all factors affecting change in demand are not affecting change in quantity demanded except income. This is also incorrect because changes in many factors can affect both demand and quantity demanded.

Option C is the correct answer. It says that many factors lead to a change in demand, but only a change in price affects the quantity demanded. This is because a change in price causes a movement along the demand curve, while a change in any other factor leads to a shift in the demand curve.

Option D is incorrect because changes in income can affect both demand and quantity demanded, while changes in other factors such as taste or the price of substitutes may only affect demand.

In summary, the correct answer is option C because a change in price is the only factor that affects quantity demanded, while changes in other factors lead to a shift in demand.