To my knowledge, the correct answer among all of the given choices is C.) Steam. If I'm not mistaken, this was the time that more trains came into use.
I hope this is the answer you were looking for and that it helps!! :)
In the the Treaty of Brest-Litovsk Russia had to abandon
Finland, Estonia, Latvia, Lithuania, Russian Poland, Part of Belarus, Ukraine, Bessarabia, and Parts of the Caucasus to the Ottoman Empire
The Germans hoped to turn most of these countries into German satellite states.
In addition, Russia had to agree to pay about US$ 6 billion in reparations to Germany.
Answer: is c
Explanation: He is a man that talks about being a billion air