Why was the lingqu canal built?
a. to irrigate farmland
b. to improve trade routes
c. to allow the emperor to travel by water to other parts of china
d. to transport troops and supplies

i will give medal and 18 points

D (This is late but :P)

Explanation:

The greatest canal built under Qin Shi Huangdi was the Lingqu Canal, which was built to transport supplies for the army. It connected two major rivers and allowed Qin Shi Huangdi's empire to expand in the southwest. A common Chinese saying is, "In the North there is the Great Wall; in the South there is the Lingqu canal."

i believe it would influence their own way of understanding things. it shall be a foundation where they can draw or start an argument.   historians are also  scientists that  have their tools of analysis and expertise to unlock a variety of difficulties such as relationships of man, origin, politics, economy, and culture. based on facts and understanding on these areas, they may shade light to extract ideas and develop options to validate a hypothesis or debunk it.