Closing price of an ETF in Xetra

Hi everyone,

can anyone explain to me what the official closing price of an ETF represents in Xetra when the last trade takes place before the closing auction at 5.30 pm and when orders in the closing auction cannot be matched?

In my opinion there are at least four options:

1.) The closing price represents the last price that could be determined during regular trading hours. For example the price that was determined for a trade that was executed at 5.28 pm.

2.) The closing price represents the best bid offer in the closing auction.

3.) The closing price represents the best ask offer in the closing auction.

4.) The closing price represents the midpoint of best bid and best ask offer in the closing auction.