Final answer:
A PDA refers to a Personal Digital Assistant, which was a handheld device used for managing personal information and featured a variety of applications.
Step-by-step explanation:
A PDA stands for Personal Digital Assistant. It is a handheld device that was popular in the late 1990s and early 2000s before the widespread adoption of smartphones. PDAs were used for managing personal data such as contacts, appointments, and tasks, and often included features like note-taking, internet browsing, and running various software applications. The correct answer to the question is a) Personal Digital Assistant.