Which of the following best defines a gift card?

A gift card is best defined as a prepaid card used for purchasing goods and services. This definition captures the essence of what a gift card is: it is preloaded with a specific monetary value that can be used to make purchases at designated retailers or sometimes broader platforms. Gift cards often come with various features, including being used in physical stores and online, allowing the cardholder to select how they wish to spend the balance.

The other definitions fall short in important aspects. Cashback on purchases refers typically to credit or reward cards that offer financial incentives for spending, but does not apply to the context of a gift card. Gift cards are not designed specifically for online transactions, as they can also be used in brick-and-mortar locations. Finally, defining a gift card as a credit card with specific rewards programs does not capture the nature of a gift card accurately, as gift cards do not involve credit or repayment terms—they are prepaid and do not accrue rewards like traditional credit cards do. Therefore, option B correctly encompasses the fundamental characteristics of what constitutes a gift card.