The correct answer is D. All of the above.
Triangulation is a surveying technique that uses a series of triangles to measure the distance between points. The area to be surveyed is divided into a series of triangles, and the angles and sides of each triangle are measured. The distances between the control stations can then be calculated using the law of sines.
Control stations are located from which detailed surveys are carried out. These stations are used to establish a reference frame for the survey, and they are also used to check the accuracy of the measurements.
Sides are not measured excepting the base line. The base line is a line that is measured directly, and it is used to establish the scale of the survey. The other sides of the triangles are calculated using the law of sines.
Triangulation is a very accurate surveying technique, and it is used for a variety of applications, including mapping, construction, and engineering.