A series of related instructions that tells the computer what to do and how to do it?

(a) program (b) command (c) user response (d) processor

Answer: a) program

Explanation:

Program is defined as the computing software that constitutes the various instructions in orderly manner so that it can create a executable task for the performance and processing. Program is coded in programming languages such as C, C++, Python, etc

Computer programs are responsible for forming a operation that is executed or made to run and then stop based on instruction set. Other options are incorrect because command is the particular instruction for specific working. User response is the feedback that is obtained from the user towards the computing. Processor is the primary unit for the all the instruction such as controlling execution, input and output maintenance, arithmetic logical operations etc. Thus, the correct option is option (a).