Between 1984 and 1989, occupancy rates in college

The stimulus offers facts about the occupancy rates in college dormitories for two time periods – 1984-1989 and 1989-1994. The more recent time period had an increase in occupancy rates at the same time fewer students were admitted. Here, a strong connection between the two statements allows us to predict that the increase in occupancy rates during 1989-1994 must be caused by more current students remaining in the dormitories. The increase in occupancy rates cannot be caused by more new students because there were fewer students admitted.

Choice (A) states that the average length of time that students remained in campus housing increased between 1989 and 1994. This matches with above explanation and is the correct answer.

Choice (B) says that the proportion of students living in campus housing was greater in 1994 than in 1989. This is an irrelevant comparison; we are concerned with the percentage of rooms that are occupied, not the percentage of students who live in dormitories.

Choice (C) mentions that student admission rates tend to decline whenever campus-housing occupancy rates rise. This is outside of the scope; we can’t infer anything about how admission and occupancy rates typically behave from this specific example.

Choice (D) indicates that campus dormitories built prior to 1989 generally had fewer rooms than did campus dormitories built after 1989. This makes an irrelevant comparison – the number of rooms is not an issue, as the stimulus gives us the information as a “"per 1,000”" rate.

Choice (E) suggests that the more rooms campus housing has, the higher its occupancy rate is likely to be. This doesn't follow from the stimulus – again, the rate of occupancy makes the actual number of rooms irrelevant.