Germany hoped to achieve a quick victory in the first world war by invading which country first?
a. russia
b. great britain
c. france
d. serbia

The best answer is  C

The plan to attack France first was a plan by the German Chief of General Staff, Alfred Von Schlieffen which he came up with way back  in 1905.

He decided that France was the enemy to be defeated first, with Russia held off until the French were annihilated. He  worked out a detailed time timetable that took into account possible French responses to German actions. He believed that Germany would defeat France within six weeks, then after that  he would turn his full force on Russia. 

Schlieffen plan was heavily modified by his successor Moltke, thus during the outbreak of WWI in 1914, it was not implemented  as Schlieffen had envisioned.

a, c, & d are correct:

they wanted lands to settle the extra population.

they wanted new markets for english goods.

they wanted to avoid civil war.

then its a law the end