Final answer:
The correct answer is option D. Option D, 'It reflects sellers reservation prices', is NOT true of a demand curve. A demand curve represents the buyer's willingness to pay, not the seller's price expectations, which is the domain of a supply curve.
Step-by-step explanation:
The student's question relates to the characteristics of a demand curve which is an important concept in economics, a sub-field of social studies. A demand curve, typically graphed with price on the vertical axis and quantity demanded on the horizontal axis, reflects buyers' willingness and ability to purchase a product at different prices. Each option given in the student's question (A to D) pertains to attributes of a demand curve except one.
Options A, B, and C correctly state that a demand curve has a negative slope, shows the amount consumers want to buy at various prices, and relates the price of an item to the quantity demanded, respectively. However, option D is incorrect because a demand curve reflects buyers' willingness to pay for a product, not sellers' reservation prices, which would instead be represented by a supply curve. Therefore, the correct answer to the question of which statement is NOT true of a demand curve is D - It reflects sellers reservations prices.