Why was quickly defeating france a key element of germany's military strategy before world war i?

a.
it needed to defeat france to win the support of great britain for its plan to immediately conquer russia.

b.
it needed to defeat france on the western front before russia could prepare to attack on the eastern front.

c.
it needed to secure french natural resources to fuel the tanks and planes that it would use to attack russia.

d.
it needed to break its alliance with france to be able to sign a new alliance to protect austria-hungary from russia