Which of the following are common video file extensions?

The selection of common video file extensions includes .mp4, .avi, and .mov. These file types are widely recognized and used for storing video content.

The .mp4 extension is known for its compatibility with various platforms and devices, making it a popular choice for streaming and sharing videos. The .avi format, developed by Microsoft, supports high-quality video and is often used for video storing and editing. Similarly, .mov, which is associated with Apple's QuickTime, is another common format used for multimedia content, particularly in professional environments.

Other options contain file extensions that do not pertain to video. For instance, .jpg and .png are image file formats, commonly utilized for photographs and graphics. The extensions .txt, .pdf, and .doc represent text and document files rather than video content, while .wav and .mp3 are audio file formats, generally related to sound rather than video. Thus, the selection featuring .mp4, .avi, and .mov is the correct choice for identifying common video file extensions.