Explanation:

- Statement: The sentence describes the extent of a sanctuary area and its deer population.

- Option 1: "in" - Generally used for enclosed spaces. Not usually for areas spread across a larger terrain.

- Option 2: "along" - Typically describes something following a line, like a river or road. Not suitable for areas.

- Option 3: "about" - Implies approximation or surrounding. Doesn’t fit well with describing the coverage of a specific area.

- Option 4: "over" - Describes something spread across a surface or area. Appropriately conveys the area covered by the sanctuary.