문제 내용: Cost pressures in liberalized markets have different effects on existing and future hydropower schemes. Because of the cost structure, existing hydropower plants will always be able to earn a profit. Because the planning and construction of future hydropower schemes is not a short-term process, it is not a popular investment, in spite of low electricity generation costs. Most private investors would prefer to finance _______ leading to the paradoxical situation that although an existing hydropower plant seems to be a cash cow, nobody wants to invest in a new one. Where public shareholders/owners (states, cities, municipalities) are involved, the situation looks very different because they can see the importance of the security of supply and also appreciate long-term investments.
선택지 1: ① more short-term technologies
선택지 2: ② all high technology industries
선택지 3: ③ the promotion of the public interest
선택지 4: ④ the enhancement of electricity supply