Final answer:
The slope of the demand curve indicates that as a consumer purchases more of a good, the additional satisfaction received from each extra unit tends to decrease, known as diminishing marginal utility. Indifference curves demonstrate this concept through their shape, as they are steeper on the left and flatter on the right. The correct answer to the student's question is D) Shift; maximized.
Step-by-step explanation:
The slope of the demand curve corresponds to the idea that the marginal utility for the first few goods is decreasing. This concept is highlighted through the examination of indifference curves, which are graphical representations used to show different combinations of two goods that provide the same level of satisfaction to a consumer. The slope of an indifference curve represents the marginal rate of substitution, which is the rate at which a consumer is willing to exchange one good for another while maintaining the same level of overall utilityIndifference curves are steeper on the left and flatter on the right, illustrating the principle of diminishing marginal utility. This principle states that as more of a good is consumed, the additional satisfaction or utility from consuming another unit decreases. The slope of the indifference curve changes because the marginal rate of substitution—reflecting the trade-off between the goods to maintain utility—also changes due to diminishing marginal utility.Therefore, the correct answer is: D) Shift; maximized.