How can you seriously expect anyone to help you answer
YOUR question, after your rash of site vandalism for the
past two hours ?
C) a unified European currency did not come about until the creation of the Euro -- instituted as an "invisible" currency in 1999 for trading but not available for common use (i.e., as a physical currency) until 2002.
The French kept the stone until Napoleon's defeat. After that, it was handed over to the English (England) because of the Treaty of Alexandria. Britain still has it in a museum on display.
Immigration decreased from 1931 to 1940 due to the Great Depression.