The correct answer is D.
Hitler and his wife called Eva Braun whom he had married only two days before, committed their double suicide in a bunker 55 feet below the chancellery which was his head quarters as chancellor.
It was a bunker that was self sufficient with its own water and electricity supply. It is believed he swallowed a cyanide capsule and then shot himself with pistol, as his "1000 -year" Reich collapsed above him, with the Red army just a day away.