Answer:
The best option to complete the sentence "The body of instruction messages should: _______?" is letter "A. divide the instructions into steps".
Step-by-step explanation:
Letter A is the best answer because it is very important to give instructions step-by-step, pointing out each action the person must take into account when developing a task. Letter B is not a reasonable answer because numeral lists are important for organizing ideas and steps point-by-point. On the contrary, letter C is a reasonable answer because it means that instruction messages can be given by writing paragraphs horizontally, although it is not the best answer because it is not clear if each step to the development of the task will be easy to understand in a current text. When someone points out instructions by steps the interlocutors can easily understand and organize its development even faster.