Answer:
Germany declared war on Russia because they wanted to also declare war on the French. In an audacious move called the Schlieffen Plan Germany had to attack Russia to delay the progress of their steam rail expansion then while the Russians are distracted attack France. Germany knew for certain if they allowed Russia to complete their rail connections the Russian with their superior numbers would overrun them.
Explanation:
It peaked in Europe between 1348 and 1350 and is thought to have been a bubonic plague outbreak caused by Yersinia pestis, a bacterium. It reached the Crimea in 1346 and most likely spread via fleas on black rats that travelled on merchant ships. It soon spread through the Mediterranean and Europe
The answer is probably c or d
I don't know but the winter war is last