The correct answer is C. To provide copyright protection. A dongle is a small hardware device that is connected to a computer to authenticate software licenses. When a company issues a dongle with their software, it's typically to prevent piracy and ensure that the software is only used by authorized users. The dongle acts as a physical key that unlocks the software, preventing unauthorized copying or sharing. Here's a brief overview of the other options: A. Source code protection: Dongles don't protect source code; they protect the software's execution. B. Wireless functionality: Dongles are typically USB devices and don't provide wireless functionality. D. Keylogger protection: Dongles don't prevent keyloggers from being used; they protect the software from unauthorized use.

C: A software dongle USB is a hardware-based electronic copy protection device. When connected to a computer, it can be used to unlock content and software functionality. Modern dongles include advanced encryption to prevent hacking and content from being stolen.