Final answer:
The total number of apartments is 4 times the number of apartments with option a.
Step-by-step explanation:
To determine the total number of apartments, we need to know the number of apartments with each combination of options. Since there are an equal number of apartments with each combination, we can assume that there are equal numbers with options a, b, c, and d. Therefore, the total number of apartments is 4 times the number of apartments with option a.
Let's say the number of apartments with option a is x. So, the total number of apartments is 4x.
We don't have enough information to determine the specific options designated by a through d.