Final answer:
The debt-to-equity ratio is the least useful for evaluating a company's ability to pay its current debts, as it measures financial leverage rather than short-term liquidity.
Step-by-step explanation:
The ratio that is least useful in evaluating a company's ability to pay its current debts as they become due is the debt-to-equity ratio. This is because the debt-to-equity ratio measures a company's financial leverage and the proportion of equity and debt used to finance the company's assets, rather than focusing on the current liabilities and the company's ability to meet those short-term obligations. When evaluating a company's liquidity and short-term debt-paying ability, the most relevant ratios are the current ratio and acid-test ratio, also known as the quick ratio, as they compare the company's current assets to its current liabilities. The debt service coverage ratio is more focused on the company's ability to pay back long-term debt with its net operating income.