Final answer:
The provided text from 'The Ethopian Story' by Heliodorus doesn't mention a character named Mary or how she killed someone. The old woman in the passage dies accidentally by impaling herself on a spear.
Step-by-step explanation:
The type of killing illustrated in the passage from 'The Ethopian Story' by Heliodorus does not correspond directly with any of the options given in the multiple-choice question (poisoning, shooting, stabbing, strangling). According to the text, an old woman was accidentally killed by a spear that struck her through the belly as she recklessly searched among dead bodies. So, if we have to choose from the provided options, stabbing by spear (though accidental and not performed by Mary) is the closest to the scenario described in the passage. The options given, however, don't accurately describe the event in the reference provided. Therefore, the answer is not available from the options A) Poisoning, B) Shooting, C) Stabbing, or D) Strangling because Mary's actions are not directly related to the killing by spear in the narrative supplied.