Final answer:
Luster is the mineral property that can be determined through observation and categorizes how light interacts with the mineral's surface as metallic or non-metallic. Hence, the correct answer is option A.
Step-by-step explanation:
The mineral property that can be determined simply by observation is luster. Luster describes how light interacts with the surface of a mineral and can be categorized as metallic or non-metallic. Metallic luster minerals do not allow light to pass through, while non-metallic luster minerals allow some light to pass through. It is important to note that a mineral may appear shiny but not necessarily metallic.