Why Does Russia Continue to Engage in a Costly War

Why does Russia continue to engage in a costly war against Chechnya instead of granting it autonomy?

A) Russia believes that if appeased,the Chechens would just ask for more.
B) Russia believes that other potential separatists would then start their own campaigns for independence.
C) Russia does not have the authority to grant autonomy to republics.
D) Russia is concerned that Chechnya would not be able to exist on its own.