Which of the following is NOT listed as a steganography cover medium?

• A. Images
• B. Email messages
• C. Video files
• D. Audio files

Answer: (B)

Steganography hides a secret payload inside another file so it remains inconspicuous. The most common cover media are those that inherently carry a lot of data and can be altered in small, imperceptible ways without drawing attention. Images, audio, and video fit this well: you can tweak pixel values, audio samples, or video frames on a tiny scale (for example, changing least significant bits) and the changes stay hidden under the surface.

Email messages, while they can carry hidden data if you apply steganography to their content or attachments, aren’t typically listed as a standard cover medium in many steganography references. They’re mainly a means of transmission and a data format rather than the type of content that people embed hidden data into in the usual sense. So, the option describing email messages is the one not typically listed as a steganography cover medium.