Which characters in a character set are used for special purposes and are non-printing?

Control characters in a character set are designated for special functions rather than representing written symbols or characters that can be printed. These characters are non-printing and are primarily used to control how text is processed or displayed. They can perform actions such as creating new lines, tabbing, or signaling the end of a transmission. For example, characters like Carriage Return (CR) and Line Feed (LF) are control characters that impact how text is formatted on output devices.

While the other options mention terms that might include special or formatting characters, they do not specifically focus on the unique category of control characters which are defined by their operational role rather than their visual representation. Understanding control characters is crucial in computing, as they help define control mechanisms in text processing and communication.