The correct answer here is D.
England had a lot on its plate. Numerous internal problems in addition to the threat from the Spain are what kept Britain isolated. It was only after King James VI ascended to the throne in 1603 and signed the Treaty of London that ended the hostilities with Spain that allowed Britain to become the world power.
I think it's C. <span>Producing agriculture past the area of the fourth ring would not be profitable.</span>
As much as C. has a partiality towards the cause of The Great War, it's most likely answer B.
The Germans declared war on the Russian Empire, guaranteed the independence of Serbia, because of their alliance backing Austria, and Serbia which the Austrians declared war on as a result of the Serbian citizen who shot the heir to the throne.
The rest of Europe's involvement was a chain reaction of countries coming to the aid of another. France with defending Russia, Britain defending Belgium, etc.
