The correct answer is (a) Personal Digital Assistants.
A Personal Digital Assistant (PDA) refers to a handheld device that combines several features like a calendar, contacts list, task manager, and sometimes even email and internet connectivity. These devices were popular before smartphones took over most of their functions. PDAs typically helped users with personal organization and productivity tasks.
For example, early PDAs like the PalmPilot or the Microsoft Pocket PC allowed users to store contacts, take notes, and sync data with desktop computers. They were often used by business professionals and tech enthusiasts for their portability and organizational tools.
Thus, Personal Digital Assistants is the correct term, referring to devices designed to help individuals manage their daily tasks.