Explanation:

• Option A (Incorrect): Infrastructure investments often involve public-private partnerships (PPPs), which are agreements between the public and private sectors to finance, build, and operate public infrastructure like hospitals and toll roads. Joint ventures are not the primary structure for such investments.

• Option B (Incorrect): Private equity funds typically use a partnership structure with a general partner managing the business and limited partners (investors) holding fractional interests. Joint ventures are not the standard structure for private equity investments.

• Option C (Correct): In real estate direct investing, joint ventures are a common partnership structure. Investors may be classified as unit holders, and this structure is frequently employed for real estate projects.