Explanation

Greenfield projects are considered high-risk infrastructure investments because:

1. Construction risk: These projects involve building new infrastructure from scratch, which carries risks of delays, cost overruns, and technical challenges.

2. Demand risk: The question specifically mentions "without guarantees of demand upon completion," meaning there's uncertainty about whether the completed project will generate sufficient revenue.

3. Regulatory and political risk: New projects often face regulatory hurdles and political uncertainties.

4. Financing risk: Greenfield projects typically require significant upfront capital investment with uncertain returns.

Comparison with other options:

• Option A (An asset with a history of steady cash flows): This represents a low-risk investment as it has proven revenue generation.

• Option B (A brownfield asset leased back to a government): Brownfield assets are existing infrastructure projects, and a leaseback arrangement with a government provides stable, predictable cash flows, making this a lower-risk investment.

Key takeaway: In infrastructure investing, greenfield projects are generally considered higher risk than brownfield projects due to the uncertainties involved in construction, demand, and initial operations.