Final answer:
The quick ratio has the least effect on a firm's sustainable rate of growth because it is a liquidity measure rather than a growth, profitability, or policy indicator.
Step-by-step explanation:
The question asks which factor has the least effect on a firm's sustainable rate of growth. When assessing the impact on the sustainable growth rate of a firm, factors such as the debt-equity ratio, capital intensity ratio, dividend policy, and profit margin are typically considered as they directly influence a company's financial leverage, reinvestment rate, operational efficiency, and profitability. However, the quick ratio, which is a measure of a company's ability to meet short-term obligations with its most liquid assets, has relatively little to do with growth potential, as it is a liquidity measure, not a performance or strategic metric like the other options.