This is called a "map legend" or a "map key". It's usually located on the side or on the bottom, whether some space is available and it lists the symbols used in the map along with their meaning.
Answer:
B: Germany was unable to repay its war debts when loans from the United States were no longer available.
Explanation:
I also had this question and this was correct.
A) All citizens are required to vote. Fun fact: In most countries with compulsory voting, failure to attend and vote can result in fines.