Statement: “Another strange thing I noticed last night was that the drawing-room lights were on.” Assumptions I & II: I. A thief must have entered the house. II. Usually, the drawing-room lights are kept off at night. Select the option that correctly identifies the implicit assumption(s).

Introduction / Context:
The speaker calls the lights being “on” at night “another strange thing.” We examine which background belief(s) must hold for the strangeness claim to make sense.

Given Data / Assumptions:

• I. A thief must have come in.
• II. Normally the drawing-room lights are off at night.

Concept / Approach:
“Strange” implies a deviation from usual practice. It does not require a specific explanation like a burglary.

Step-by-Step Solution:
1) Core observation: lights were on at night.2) Reason for calling it strange: presumes a usual pattern of lights being off (II).3) The statement does not assert or need the conclusion that a thief entered; that would be a separate inference.

Verification / Alternative check:
Other explanations (forgot to switch off, family member awake) are consistent; hence I is not necessary.

Why Other Options Are Wrong:
Only I: unsupported leap. Either I or II: only II is needed. Neither: incorrect because “strange” demands a baseline norm. Both: I adds unjustified certainty.

Common Pitfalls:
Inferring specific causes from anomalies without evidence.

Final Answer:
Only assumption II is implicit.