What is a CAPTCHA used for in computing?

A CAPTCHA, which stands for "Completely Automated Public Turing test to tell Computers and Humans Apart," is specifically designed to differentiate between human users and automated programs (bots). The primary purpose of a CAPTCHA is to prevent automated systems from engaging in actions that should only be performed by humans, such as submitting forms, creating accounts, or accessing specific content. By presenting challenges that require human cognitive abilities, such as identifying distorted text, selecting images, or solving puzzles, CAPTCHAs effectively verify that the response comes from a human, thereby enhancing the security and integrity of online systems.

Other options pertain to aspects that are not directly linked to the main function of a CAPTCHA. For instance, while creating secure passwords is important for online security, it does not fall within the scope of what CAPTCHA is designed to do. Similarly, enhancing user experience and improving data storage are relevant to computing but are not the fundamental purpose of CAPTCHAs. Thus, the correct choice highlights the unique role that CAPTCHAs serve in online environments.