After early morning success , I fell into a deep deep pit . I found another " maniac " to play heads up . I got down pretty quick when the guy flopped a straight vs my flopped 2 pair . Big pot ... lost my stack .

Options are:
[i] None of the above choices .
[ii] Because he was playing with a maniac .
[iii] Because a straight beats a 2 pair .
[iv] Because the writer fell into a deep pit .
Answer the following question: Why did the writer lose their stack ?
[iii]