Critical reasoning — identify implicit assumptions Statement: To investigate the murder of the lone resident of a flat, the police interrogated the domestic servant, the watchman of the multi-storeyed building, and the liftman. Assumptions: I. These individuals can provide leads or clues about the suspected murder. II. Generally, in such cases, persons known to the resident are directly or indirectly involved.

Introduction / Context:
Police begin an investigation by questioning people with proximity: servant, watchman, liftman. We must determine which assumption is necessary for this initial step.

Given Data / Assumptions:

• Action: Interrogation of nearby or familiar personnel.
• Assumption I: These people might have noticed suspicious activity or have relevant information.
• Assumption II: Typically, someone known to the victim is involved in such crimes.

Concept / Approach:
Investigative practice starts by interviewing those with access or observation potential. This requires assuming they can provide clues, not necessarily that acquaintances are generally perpetrators. The latter is a broader criminological claim and not required to justify these interviews.

Step-by-Step Solution:

Verification / Alternative check:
Standard operating procedure interviews potential witnesses regardless of general statistics about offender familiarity.

Why Other Options Are Wrong:

• Only II / Either / Both: Add an unnecessary generalization about offender identity.
• Neither: Ignores the informational rationale for questioning.

Common Pitfalls:
Confusing witness-proximity logic with claims about who typically commits such crimes.

Final Answer:
Only assumption I is implicit