Step 1: Understanding the Six Ws.
- The Six Ws — who, what, when, where, why, and way (how) — are used in the problem definition stage to clearly outline the issue before designing the questionnaire.
- This ensures that the scope, respondents, timing, location, reasons, and method are identified clearly.
Step 2: Eliminate wrong options.
- (b) Choosing question wording comes later in questionnaire design, after defining the issue.
- (c) Avoiding generalizations is part of phrasing questions, not defining the problem.
- (d) Determining content is also a later stage.
\[
\boxed{(a)}
\]