Correct Option: C. A change in consumer preferences favoring the good
Detailed Explanation:
To understand why option C is the correct answer, we need to delve into the concept of demand and the factors that can cause a shift in the demand curve.
- Understanding Demand Curves:
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A demand curve represents the relationship between the price of a good and the quantity demanded by consumers. When we talk about a shift in the demand curve, we are referring to a change in demand at every price level, not just a change in quantity demanded due to a price change.
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Normal Goods:
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Normal goods are those for which demand increases as consumer income rises. Conversely, demand decreases when consumer income falls. However, other factors can also influence demand.
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Factors Causing a Shift in Demand:
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Several factors can cause the demand curve to shift to the right (an increase in demand):
- Changes in consumer preferences
- Changes in consumer income
- Prices of related goods (substitutes and complements)
- Expectations about future prices
- Number of consumers in the market
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Analyzing Option C:
- C. A change in consumer preferences favoring the good:
- If consumers develop a preference for a particular good, this will lead to an increase in demand for that good at all price levels. For example, if a new study shows that a certain food item is particularly healthy, more consumers may want to buy it, shifting the demand curve to the right.
Why the Other Options Are Incorrect:
- A. An increase in the price of a substitute good:
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When the price of a substitute good increases, consumers are likely to buy more of the normal good instead. This would indeed increase the quantity demanded of the normal good, but it does not shift the demand curve itself. Instead, it results in a movement along the demand curve for the normal good.
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B. A decrease in consumer income:
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For normal goods, a decrease in consumer income would lead to a decrease in demand, shifting the demand curve to the left. This is contrary to what we are looking for, as it does not cause a rightward shift.
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D. An increase in the price of the good itself:
- An increase in the price of the good typically leads to a decrease in the quantity demanded, resulting in a movement along the demand curve rather than a shift of the curve itself. This is known as the law of demand.
Summary of Key Points:
- A rightward shift in the demand curve indicates an increase in demand at all price levels.
- A change in consumer preferences favoring a good (Option C) is a primary factor that can lead to such a shift.
- Other options either describe movements along the demand curve or shifts in the opposite direction.
- Understanding the distinction between shifts in demand and movements along the demand curve is crucial for analyzing market behavior.
Revision Summary:
- A rightward shift in the demand curve indicates increased demand at all price levels.
- Consumer preferences significantly influence demand for normal goods.
- An increase in the price of substitutes leads to a movement along the demand curve, not a shift.
- Decreases in income for normal goods result in decreased demand, shifting the curve left.