Statement — “Please do not lean out of the running bus,” reads a notice posted inside a tourist bus.\n\nAssumptions —\nI. Leaning out of a moving bus is dangerous.\nII. Passengers are likely to pay attention to and follow such safety notices.

Introduction / Context:
Safety notices inside public transport aim to prevent harm. Posting “do not lean out” presupposes that the behavior is risky and that notices have at least some deterrent effect on passenger conduct. Otherwise, the sign would be unnecessary or ineffective.

Given Data / Assumptions:

• Notice content: avoid leaning out of a moving bus.
• I: the behavior poses danger (injury risk from poles, vehicles, trees, or sudden swerves).
• II: passengers will attend to and obey such notices to some degree.

Concept / Approach:
For the notice to be rational, the operator must believe both that a real hazard exists and that communication mitigates it by influencing behavior. Therefore both assumptions are implicit in the act of posting the warning.

Step-by-Step Solution:

Verification / Alternative check:
Even partial compliance lowers risk, validating II. The ubiquity of such notices indicates that operators deem the behavior dangerous, validating I.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming a notice requires perfect compliance; it only assumes some meaningful effect.

Final Answer:
Both Assumption I and II are implicit.