Final answer:
Without the actual scatter plot, it's challenging to determine which statement about the correlation between the ages of used cars and their prices is best supported. If a scatter plot shows the price decreases with age, option D is correct. However, without specific data or the scatter plot, neither options A, B, nor C can be confirmed accurately.
Step-by-step explanation:
Without the actual scatter plot to assess, we can use the provided context to answer the student's question about the correlation between the age of used cars and their prices. If we had the scatter plot and observed that as the age of the used cars increases, the price tends to decrease, then option D, which states that the price of a used car steadily decreases with age, would be the best-supported statement by the data. This is based on the common understanding that the value of most cars depreciates over time.
For options such as A and C, which speak to the number of cars below a certain age or price, we would need specific data points from the scatter plot to be able to confirm the statement's accuracy, and so without this graphical information, we cannot confirm these statements. Option B, on the other hand, requires only a single data point (the oldest car's price), but again without the scatter plot, it's impossible to confirm if the oldest car indeed has the lowest price.