Task: Question Answering
Input (English): The construction of Hoover Dam on the Colorado River resulted in abundant freshwater and electrical power for the region. Which of these is a disadvantage of the construction of Hoover Dam?  
 (A) an increase in flooding downstream (B) an increase in regional humidity (C) a decrease in the amount of river ecosystems (D) a decrease in the amount of water for irrigation
Output (English): C