Final answer:
The consumer finance services industry has the highest debt-to-equity ratio because they rely heavily on debt to finance their operations, while firms in oil and gas have the lowest ratio due to their capital-intensive operations.
Step-by-step explanation:
The reason why the consumer finance services industry has the highest debt-to-equity ratio is because this industry relies heavily on debt to finance its operations.
Consumer finance companies provide loans and credit to individuals, so they need to borrow funds themselves to have enough capital to lend. On the other hand, firms in oil and gas have the lowest debt-to-equity ratio because their operations are capital-intensive and require significant upfront investments. These firms often have valuable assets, such as oil fields or refineries, which serve as collateral for loans, reducing the need for high levels of debt.