Power barges" are mobile power plants on ships, usually gas-powered turbines. During the 1990s, power barges became a popular way of providing energy to low-income nations. Companies including Raytheon, Westinghouse, Smith Cogeneration, and Amfel built floating power plants for customers such as Bangladesh, Ghana, Haiti, Kenya, and Malaysia, as well as intermediaries such as the Power Barge Corporation. How might power barges relate to the concept of holdup?

1. There exists a vertical relationship between low-income countries and companies that produce power plants.

2. When an ordinary power plant is built, it cannot be moved, so it amounts to a relationship-specific investment.

3. Governments may promise power companies a favourable rate on electricity so that they build the power plant, but then renegotiate that rate later.

4. All of the above