What is the computer's instruction set?
a. the basic set of commands that a computer can execute
b. the rules for using a high-level programming language
c. the pseudocode used to express an algorithm
d. the syntax of a high-level language

Option (A) is the correct answer for the above question.

Explanation:

A computer is a device that gives the output after processing the given inputs. "Inputs" is a line of segments which is used by the human being to take some output from the computer system. This "inputs" is a combination of some instructions on which a user wants to instruct about the work of a computer.

Actually, A computer is not a human being, It is a machine so it works on the instruction of human being. So human being needs to give the commands to the computer system which is also known as an instruction set.

In the above question option "a" also suggests the same concept which describes above. hence it is the right answer. The other option is not valid because--

they really not common the os x is just a better version of the os like in iphone theirs xr and their xs