According to the passage, what did nature represent to Isadora Duncan

A．It dropped due to the weakness of the eurozone economies and the inexperience of the European Central Bank in dealing with the international markets.
B．People in most European countries refused to use euro instead of their own currency.
C．Counterfeiters made a lot of fake notes since people were not familiar with the new currency.
D．Some countries are not ready for the euro. They stopped using euro in daily purchasing.

A．They can be used normally to mail a letter.
B．They can only be used for exhibition.
C．They are used to attract more tourists.
D．They are used to post on famous buildings.