Which of the following practices is considered credit card fraud?

Using a stolen credit or debit card is a clear example of credit card fraud because it involves unauthorized use of someone else's financial information with the intent to deceive. This act violates legal and ethical standards and is a criminal offense. Credit card fraud encompasses various actions where an individual obtains or uses a credit card without the account holder's permission, which is precisely the scenario outlined in the correct response. Engaging in such practices can lead to significant legal consequences and reputational damage for the perpetrator.

The other options involve activities that, while possibly unethical or risky, do not constitute fraud in the legal sense. For example, using a personal credit card for business purchases could violate company policy but does not involve deception regarding the ownership of the credit card itself. Transferring balances among cards is a standard financial practice used for managing debt, and acquiring multiple credit cards for rewards is a common strategy consumers might use to maximize benefits; neither action involves theft or unauthorized use of another's identity.