Consider the following infrastructure sectors: 1. Affordable housing 2

Examining the listed sectors:
1. **Affordable housing:** Providing adequate and affordable housing is a key component of sustainable urban development (SDG 11) and poverty reduction (SDG 1). Sustainable infrastructure initiatives often include housing projects.
2. **Mass rapid transport:** Developing efficient and sustainable public transport systems is crucial for sustainable cities (SDG 11), reducing emissions (SDG 13), and facilitating economic activity. It is a major area of focus for sustainable infrastructure investment.
3. **Health care:** Building and improving healthcare infrastructure (hospitals, clinics, supply chains) is fundamental to achieving good health and well-being (SDG 3). Sustainable infrastructure initiatives recognize the importance of resilient and accessible health facilities.
4. **Renewable energy:** Investing in renewable energy sources (solar, wind, hydro, etc.) is vital for ensuring access to affordable, reliable, sustainable, and modern energy (SDG 7) and combating climate change (SDG 13). This is a core focus area for sustainable infrastructure investment globally, including for S3i.

Based on the mandate and typical focus areas of sustainable infrastructure development initiatives like UNOPS S3i which are aligned with the SDGs, all four sectors listed are critical areas for investment. UNOPS has indeed been involved in projects and partnerships related to these sectors through its S3i initiative. Therefore, the initiative focuses its investments on all four of the listed infrastructure sectors.