To support the analyst's assertion, we must identify an assumption that helps explain why scarcity drives such large price increases.
Analyzing Each Option:
(A) In the housing market, there generally must be at least five buyers per seller in order to cause larger than normal increases in price.
Analysis: This option provides a potential ratio of buyers to sellers necessary to cause price increases, but the argument is about general scarcity rather than a specific ratio. The ratio of buyers to sellers is not discussed, and this option introduces new information that is not critical to the argument.
Conclusion: This is not necessary.
(B) Increases in demand often reflect an influx of new buyers into the marketplace or an unusual increase in buying power on the part of the customer.
Analysis: This option explains a potential cause of the increase in demand. However, the argument is not focused on the cause of increased demand but rather on the relationship between scarcity (high occupancy rates) and price increases. This does not directly support the analyst’s claim about scarcity causing price increases.
Conclusion: This is not necessary.
(C) The U.S. housing market showed a larger than average increase in the 1990s across the country, not just in crowded urban areas.
Analysis: This option introduces information about a broader trend in the U.S. housing market. However, the argument focuses on specific urban markets, and the national trend does not affect the relationship between scarcity and price increases in those crowded areas.
Conclusion: This is not necessary.
(D) Price increases do not cause people to withhold their houses from the market in the hopes that prices will increase even further in the future.
Analysis: This option addresses the potential effect of price increases on seller behavior. If homeowners withheld their houses from the market in anticipation of future price increases, the scarcity would worsen, and prices could rise even more. For the analyst's assertion to hold, it is assumed that price increases do not trigger a withholding of houses that would further affect market dynamics.
Conclusion: This is necessary. The assumption that sellers are not withholding houses is important for the price increases to be purely driven by scarcity, rather than speculative behavior.
(E) A significant rise in housing prices in a specific area may cause some potential buyers to relocate to other, less pricey areas.
Analysis: This option suggests that price increases could drive buyers away, reducing demand in the original area. While this could be relevant to understanding long-term market shifts, it does not directly support the analyst’s assertion that scarcity leads to large price increases. Instead, it discusses the potential consequences of such increases.
Conclusion: This is not necessary.
Correct Answer: (D)Explanation:
The assumption that price increases do not cause people to withhold their houses from the market is essential for the analyst's assertion that scarcity directly drives larger-than-normal price increases. If people were withholding their houses in anticipation of further price increases, it would affect the supply and demand dynamics differently, potentially invalidating the analyst's claim. Therefore, (D) is the assumption that supports the assertion.