A European option is different from an American option in that

A、oneistradedinEuropeandoneintradedintheUnitedStates.
B、Europeanoptionscanonlybeexercisedatmaturity;Americanoptionscanbeexercisedpriortomaturity.
C、EuropeanoptionstendtobeworthmorethanAmericanoptions,ceterisparibus.
D、Americanoptionshaveafixedexerciseprice;Europeanoptions'exercisepriceissetattheaveragepriceoftheunderlyingassetduringthelifeoftheoption.