Statement — Some strains of mosquitoes have become resistant to chloroquine, a widely used antimalarial.\nCourses of Action:\nI. Stop selling chloroquine.\nII. Researchers should develop new medicines for patients affected by such mosquitoes.\nIII. All malaria patients should be checked to identify the causal mosquito.

Introduction / Context:
Drug resistance necessitates therapeutic innovation and better diagnostics, not wholesale withdrawal of an otherwise useful drug where it still works.

Given Data / Assumptions:

• I: Ban/stop chloroquine sales.
• II: Develop new antimalarials or effective combinations.
• III: Identify causal species/likely resistance profile before treatment.

Concept / Approach:
I is overbroad; chloroquine may still be effective for non-resistant infections/regions. II is essential to overcome resistance. III improves case management (species test/RDTs, clinical algorithms) enabling appropriate drugs.

Final Answer:
Both II and III follow.