Their own actions or decisions because their downfall is the characteristic that tragic heroes shares, hence option D is correct.
Hamartia is a catastrophic blunder made by the hero or heroine that ultimately leads to some acts that result in the person's untimely death.
The hero's collapse is therefore primarily her/his own fault, the outcome of free will rather than accident, villainy, or some overarching, malignant fate.
In fact, the tragedy is usually triggered by some error of judgment or some character flaw that contributes to the hero's lack of perfection noted above. This error of judgment or character flaw is referred to as hamartia, which translates as "tragic flaw."
Therefore, their own actions or decisions because their downfall is the characteristic that tragic heroes shares.
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