Please help me
Why were European nations willing to give up their colonies after WWII?

They couldn't afford to keep them anymore.  Colonies were expensive, and cost more to maintain than they produced.

the answer to your question is:

strong-mayor system

no options provided, here,but the answer to this question is often: a historian cites a japanese newspaper article published a year after the end of world war ii in order to draw conclusions about the effect of the war on the japanese economy.

clearly from the answer, the historian alludes to historical sources,and records to aid in analyzing and drawing conclusion on the effect of the war on the economy of japan.