Final answer:
Revision is a critical stage in the writing process, which includes refining word choice for clarity and clarifying vague ideas, making options I and IV part of the revision steps.
Step-by-step explanation:
The revision process in writing involves various steps that aid in refining a draft to communicate ideas more effectively. Among the options provided, first revising word choice for clarity (I) and clarifying vague ideas (IV) are both activities involved in revising. Selecting a topic (II) comes before drafting, and writing a first draft (III) is also a preliminary step before revision. Therefore, the steps that belong to the revision process are revising word choice for clarity and clarifying vague ideas - making option (a) I and IV the correct answer.