Detailed Answer
(c) The requirement is to identify a set of rules for exchanging
data between two computers. Answer (c) is correct
because a protocol is such a set of rules. Answer (a) is incorrect
because the term “communicator” is very general and has no
specific meaning in this context. Answer (b) is incorrect because
while an operating system controls the execution of computer
programs and may provide various services related to computers,
it is not a set of rules for exchanging data. Answer (d) is incorrect
because transmission speed is the speed at which computer processing
occurs.