The correct answer is: A. Triangulation surveying.
A station pointer is a surveying instrument used to mark the position of a survey station. It is typically a small, lightweight rod with a pointed tip that is inserted into the ground. The station pointer is used in triangulation surveying, which is a method of surveying that uses a network of triangles to determine the position of points on the Earth’s surface.
Astronomical surveying is a method of surveying that uses the positions of stars to determine the position of points on the Earth’s surface. Hydrographical surveying is a method of surveying that is used to determine the depth and shape of the seabed. Photogrammetric surveying is a method of surveying that uses photographs to create a three-dimensional model of the Earth’s surface.
Triangulation surveying is the most accurate method of surveying, and it is used for a variety of purposes, including the construction of roads, bridges, and buildings. Astronomical surveying is used to determine the position of points on the Earth’s surface for navigation and other purposes. Hydrographical surveying is used to determine the depth and shape of the seabed for navigation and other purposes. Photogrammetric surveying is used to create three-dimensional models of the Earth’s surface for a variety of purposes, including the construction of maps and the study of natural disasters.