Final Answer:
A series of instructions that can be grouped together as a single command and are often used to automate a complex set of tasks or a repeated series of tasks is known as a macro. Option B is the answer.
Step-by-step explanation:
Rootkit (Option a): A rootkit is a malicious software that provides unauthorized access to a computer system, but it is not a series of instructions used to automate tasks.
Macro (Option b): Macros are sequences of instructions grouped together as a single command. They are often used to automate repetitive tasks in software applications.
Program (Option c): A program is a set of instructions that performs a specific task or set of tasks. While it is a broader term, a macro can be considered a type of program.
Process (Option d): A process refers to a program in execution, representing the dynamic aspect of a program running on a computer.
Option B is the answer.