A currency and its cash can have different starting dates.
Cash can be handed over directly: coins or banknotes. Non-cash money exists as balances in accounts and moves through transactions such as bank transfers. The question explicitly concerns physical means of payment, not the earlier start of the euro for non-cash transactions.
At the beginning of 2002, the joint cash changeover started in twelve countries. Germany was among them. This makes 2002 the appropriate year, even if another source has already taught you 1999 as the year the euro was introduced.
The other three answers
The three other years do not mark the start of euro cash payments in Germany.
1995
1995 predates the introduction of euro cash. For coins and banknotes, the relevant date is the beginning of 2002.
1998
1998 is also too early. Even the euro’s introduction as non-cash money in 1999 must be distinguished from the later start of cash.
2005
2005 is too late: Germany had already been using euro banknotes and coins since 2002.
A historical cash launch is not a current membership count.
The twelve countries describe the beginning of the cash changeover in 2002. The euro area later grew. Not every EU member state uses the euro; EU membership and participation in the euro are different questions.
The question asks neither for an exchange rate nor for every transitional arrangement. The clear distinction is enough to identify the year: the euro as non-cash money since 1999, euro cash since 2002.
Euro cash changeover, 2002 · European Central Bank ↗“In cash” means coins and banknotes: 2002.
Pay attention to the payment method as you read. A question without “in cash” may refer to a different historical starting point.
Three words for this question
- das Bargeldcash
- Money in the form of coins and banknotes.
- das Buchgeldnon-cash money
- Money held as account balances, as distinct from coins and banknotes.
- in Umlauf kommento enter circulation
- To be issued and used as a means of payment.