Return on investment ratio is the ratio of which two financial elements?

The return on investment (ROI) ratio is indeed defined as the ratio of net income to owner's equity. This relationship allows stakeholders to understand how effectively a company is using the equity invested by its owners to generate profit. By calculating ROI, businesses can assess the profitability of investments and make informed decisions regarding resource allocation.

Net income represents the profit earned after all expenses, taxes, and costs have been accounted for, while owner's equity reflects the residual interest in the assets of the entity after deducting liabilities. Therefore, expressing net income as a proportion of owner's equity gives a clear picture of how well each dollar of equity is yielding profit. A higher ROI indicates more efficient use of equity financing.

The other options do not correctly align with the definition of ROI. The second choice relates to the relationship between market price and earnings but does not measure the efficiency of equity use. The third option discusses inventory management and cost but does not pertain to investment returns. Lastly, the fourth option examines the efficiency of credit sales management without connecting back to equity profit-making.