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."

hello,

the steamboat is your answer.

it seems like its the only form of transportation on the choices.

the answer would more than likely a.)falling crop prices  

hope the answer is right and ,either way have a nice day.