Concept:On a topographical map, a capital letter followed by a height value indicates a trigonometrical station.
Explanation:The symbol
A950 contains the station letter
A and the height
950.
This is different from a bench mark, which is labelled
BM.
It is also not a spot height, because a spot height is shown only as a dot with a number.
A letter plus a height represents a fixed survey point used for accurate reference.
Such a point is called a trigonometrical station.
Answer:D. trigonometrical station
