Answer: Option C
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Explanation: In simple words, sunk cost refers to the cost that a company has already incurred and cannot recover it in future in any way for example- market research cost before introducing a product in the market.
No matter whether the organisation takes the prospective project or not these costs are not recoverable, Â hence they are considered to be irrelevant with respect to decision making.
Hence we can conclude that the correct option is C.