Which of the following tools is used to attack the Digital Watermarking?

Active Attacks is a broad category of attack methodology (e.g., modifying data in transit), not a specific tool used against digital watermarking.

2Mosaic is a known digital watermark attack tool that defeats watermarking by dividing an image into small mosaic segments, disrupting the embedded watermark pattern without visibly degrading the image. It is specifically categorized as a watermark removal or attack tool in steganography and digital rights management contexts. This makes it the only answer that is a named tool designed explicitly to defeat digital watermarking.

Steg-Only Attack is a type of steganalysis attack model (where the attacker has only the stego-object), not a tool targeting digital watermarks.

Gifshuffle is a steganography tool used to hide secret messages inside GIF images, not a tool for attacking or removing digital watermarks.