Final answer:
The Process Control Block is a Data Structure that contains crucial information about a process needed for process management in operating systems.
Step-by-step explanation:
The Process Control Block (PCB) is b) Data Structure. It is a critical data structure in an operating system that contains important information about the process such as its state (running, waiting, etc.), program counter, CPU registers, memory limits, list of open files, and other process-specific information that the system needs to manage processes effectively.
The PCB is not a process type variable, a secondary storage section, nor a block in memory, but rather it serves as a repository of process information that allows an operating system to switch between processes efficiently in a multitasking environment, through a process known as context switching.