Which of the following would be considered a deceptive act or practice?

The answer is grounded in the understanding of deceptive acts and practices as defined by consumer protection laws. A pre-approval offer that advertises a "0% APR and No Fee" while actually including a hidden processing fee constitutes a misleading representation. Consumers are led to believe that they will not incur any costs associated with the offering, and the unexpected processing fee directly contradicts this promise. This discrepancy is likely to confuse or mislead consumers, making it a clear example of a deceptive practice.

In contrast, the other options do not present the same level of deception. Offering "No Balance Transfer Fee" for transfers within a specified timeframe is straightforward and doesn’t mislead about the terms involved. Similarly, providing information on optional credit protection plans while processing an application is transparent as long as the options are clearly laid out, and there is no misrepresentation involved. Therefore, it is the clear, misleading nature of the pre-approval offer that makes it an act of deception.