Question

what are credit cards a substitute for? credit limits cash credit ratios

Explanation:

Credit cards are a financial instrument that allows users to make purchases without using physical cash. They provide a convenient alternative for transactions where cash might be cumbersome or less secure. Credit limits refer to the maximum amount a cardholder can borrow, credit ratios are related to financial assessment metrics, neither of which are substitutes in the context of transactional medium like cash.

Answer:

cash