Detailed Explanation:

Answer: Option 3 — Only three

The UNOPS Sustainable Investments in Infrastructure and Innovation (S3i) initiative focuses on three specific infrastructure sectors: Affordable Housing, Renewable Energy, and Health Infrastructure. Mass rapid transport is not included in the S3i investment mandate.

✅ Affordable housing – Included: S3i invests in sustainable, affordable housing to address global housing shortages.
❌ Mass rapid transport – Not Included: Transport infrastructure is not part of the S3i initiative's specific investment focus.
✅ Health care – Included: Health infrastructure is a core focus area to improve access to essential medical services.
✅ Renewable energy – Included: Clean energy and climate-resilient infrastructure are key investment areas for S3i.

📝 Short Notes: UNOPS S3i Initiative

• Full Name: Sustainable Investments in Infrastructure and Innovation (S3i)
• Launched by: United Nations Office for Project Services (UNOPS)
• Primary Objective: Mobilize private capital for sustainable infrastructure investments aligned with SDGs
• Three Focus Sectors: Affordable Housing, Renewable Energy, and Health Infrastructure
• Investment Approach: Blended finance model combining public and private resources
• Target Regions: Primarily developing countries with infrastructure deficits
• Alignment: Supports SDG 3 (Health), SDG 7 (Energy), SDG 9 (Infrastructure), and SDG 11 (Cities)