ANS:B - 1770

In 1770, the concept of stadia tacheometry had not yet been developed. During this time period, surveying techniques were undergoing gradual evolution, but the specific method of stadia tacheometry, which involves using stadia hairs in the reticle of a surveying instrument to measure distances, angles, and elevations, had not yet been conceived. The late 18th century was a time of significant advancements in various fields of science and engineering, including surveying and geodesy. However, it wasn't until the 19th century that the principles and techniques of stadia tacheometry were refined and formalized by figures like Carl Pulfrich and Carl W. F. von Hahn. These developments in surveying techniques during the 19th century paved the way for more efficient and accurate methods of measurement in civil engineering, construction, and land surveying projects. Therefore, attributing the discovery or development of stadia tacheometry to the year 1770 is historically inaccurate.