What was one cause of the Russian Revolution? A
There was an unequal distribution of wealth between the elite and the lower class.
B
Members of the imperial family were accused of conspiring with the Germans.
С
The tsar lost the first democratic election in Russia and refused to abdicate.
D
Communist revolutionaries from China spread their ideology in Russia.

Explanation:

Russian Revolution, also called Russian Revolution of 1917, two revolutions in 1917, the first of which, in February (March, New Style), overthrew the imperial government and the second of which, in October (November), placed the Bolsheviks in power.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.