B. Russia backed out of the war.
The Treaty of Brest-Litovsky signified Russia's exit from the War. In November of 1917 Russia was having its own problems. During this time the Russian government was being overthrown and a communist regime being implemented by Lenin.
I think it was the populations and wealth of people.
You haven't listed the choices.
The correct one will be the number with the biggest absolute value ...
the biggest number when you take away all the plus, minus, BC,
BCE, AD, CE, and all that stuff. Just the biggest number, period.