Cause–Effect Pairing:\nI) Residents in the locality decide to launch a cleanliness drive.\nII) Civic authorities have recorded many cases of cholera and gastroenteritis in the city.

Introduction / Context:
Public-health data often triggers community action. Here, disease incidence (II) is likely the reason residents organize a cleanliness drive (I).

Given Data / Assumptions:

• II) Many cholera/gastro cases recorded by civic authorities.
• I) Residents decide on a cleanliness drive.
• No contrary timing details are given.

Concept / Approach:
Disease outbreaks commonly provoke preventive/community mitigation efforts (sanitation, hygiene campaigns), making II → I a natural causal path.

Step-by-Step Solution:
1) Recognize public-health spike as a trigger for local action.2) Cleanliness drives aim to reduce transmission vectors (contaminated water/food, poor waste disposal).3) Therefore, II causes I.

Verification / Alternative check:
Reversing the direction (I → II) would imply the drive caused disease, which is illogical.

Why Other Options Are Wrong:
(a) mis-assigns causality; (c) and (d) ignore an evident linkage.

Common Pitfalls:
Missing the typical trigger–response sequence in civic health scenarios.

Final Answer:
Statement II is the cause; Statement I is its effect.