Why did the french invade the german industrial region of the ruhr in 1923?
a. the french believed the industrial area would further its own economic recovery.
b. the germans failed to maintain control over the area and radical factions were causing trouble there.
c. the french meant to force the germans to continue paying the war reparations.
d. the germans threatened to take back the rhine region that was lost after the war, provoking a french invasion.