Explanation:

When a firm reports negative earnings for the most recent fiscal year, the trailing price-to-earnings (P/E) ratio becomes negative and loses its meaningfulness as a valuation metric. In such cases, practitioners often turn to alternative multiples:

• Price-to-cash-flow ratio (Option B): This can be meaningful because cash flows might remain positive despite the negative earnings.
• Leading price-to-earnings ratio (Option C): This replaces the negative earnings with forecasted positive earnings, making it a viable alternative.

Thus, the trailing P/E ratio (Option A) is the least likely to be meaningful under these circumstances.