umm... here are other two methods

-- get it from default trace
DECLARE @trc_path VARCHAR(500)
SELECT @trc_path=CONVERT(VARCHAR(500),value) FROM fn_trace_getinfo(DEFAULT)
WHERE property=2

print @trc_path
SELECT TEXTData,HostName,ApplicationName,DatabaseName,LoginName,SPID,StartTime,EventSequence
FROM fn_trace_gettable(@trc_path,1) fn
WHERE TEXTData LIKE '%Configuration option%'
-- get it from errorlog
declare @sysconfigchanges TABLE
(
    RowID int IDENTITY PRIMARY KEY,
    EntryTime datetime,
    source varchar(50),
    LogEntry varchar(4000)
)

insert into @sysconfigchanges
exec sp_readerrorlog 0,1,'Configuration option'

select * from @sysconfigchanges where rowid=(select max(rowid) from @sysconfigchanges)