Final answer:
Rent control policies often result in a decrease in the available rental housing units and lower quality housing, as landlords face reduced profits and invest less in property maintenance. Thus, options (a) and (c) from the list provided are correct.
Step-by-step explanation:
When cities prevent landlords from charging market rents due to rent control policies, several long-run outcomes are commonly observed. First, the quantity of available rental housing units falls, as landlords may convert rental properties into co-ops and condos, or exit the rental market altogether. This reduction in supply can lead to a housing shortage. Secondly, landlords earn lower profits from renting housing units, which often results in them spending less on maintenance and essentials, leading to lower-quality housing. Therefore, options (a) and (c) from the list provided are correct, while options (b), (d), and (e) are not.