Question

Why must old currency be taken out of circulation When new currency is made?

Answer 1

C Too much currency in an economic system will cause inflation

Answer 2

If there are too many units of any currency in circulation, this will cause an over-abundance of currency which will lead to inflation where value is lost. Retaining old currency will lead to confusion, so it's important that when a new currency is introduced a deadline is imposed on when an old currency must be used or exchanged by.