How many walls are shared with other apartments for the apartment labeled "X"?

The apartment labeled "X" shares three walls with neighboring apartments. This is a common configuration in multi-unit housing, where each apartment typically has walls adjacent to one or more other living spaces. In a standard setup, one wall would usually be shared with the apartment on one side, another with the apartment on the opposite side, and a third wall could potentially face a corridor or connect with a common area.

Considering the options, only the selection indicating three shared walls fits the typical arrangement of an apartment layout and is therefore the correct answer. If there were four or five walls shared, it would imply a different and more uncommon spatial arrangement, possibly suggesting that the apartment is at a corner or has a unique design, which is less likely.