單選題

Despite the economic and environmental hurdles, desalination is becoming increasingly attractive as human beings are using up fresh water from other sources. At present, desalinating seawater is the only viable way to provide water to growing populations in rural areas of the Middle East and North Africa. Therefore, the race is on to find a cheaper, cleaner, and more energy-efficient way of desalinating seawater, and promising new findings are being reported.

 (A) Gloomy.

 (B) Hopeful.

 (C) Conservative.

 (D) Doubtful.