Which country's gas station had the first paid cusomer in 2012/8/25?
'2012/8/25' can be represented by '2012-08-25'
SELECT T2.Country FROM transactions_1k AS T1 INNER JOIN gasstations AS T2 ON T1.GasStationID = T2.GasStationID WHERE T1.Date = '2012-08-25' ORDER BY T1.Time DESC LIMIT 1