16. Which communications management practice includes specifying all of the communications systems and platforms that parties will use to share information?

D). Agreements.

Explanation:

Communication management practice is described as the organized process of systematic planning, execution, observation, followed by a revision of all the modes of communication present or involved in an organization or among different institutions or organizations.

As per the question, 'agreements' would be the communications management practice that involves the specification or statement of all the systems as well as platforms of the communication that the parties would be required to share information. Both the parties mutually agree to this statement that assists in managing the communication in the organization effectively. Thus, option D is the correct answer.