What happened in russia in 1917 that led the united states to justify its involvement in world war i as a fight for democracy?
a) russia signed a military defense treaty with france and great britain.

b) russia signed the treaty of brest-litovsk and made peace with the germans.

c) russian revolutionaries overthrew the czar and established a provisional government.

d) russian bolsheviks, under vladimir lenin's leadership, toppled the provisional government.