Which of the following features was added to the revised passport card?

The revised passport card includes a ghost image that covers personal information as one of its security features. This ghost image is designed to enhance the card's security against counterfeiting and unauthorized alterations by displaying a faint representation of the photo that makes it difficult for anyone to replicate the card accurately. This feature is crucial for identity verification and ensures that only legitimate passport cards can be used for border crossings.

The other options, while potentially valid features in their own contexts, do not reflect the specific updates made to the passport card, which prioritizes security enhancements such as the ghost image. The inclusion of this type of feature is part of a broader effort to ensure that official documents are protected and trusted by authorities at border points.