Task: Question Answering
Input (English): The bacterium Brucella abortus causes fever in humans. Biologists studying this bacterium found that when exposed to light, the bacterium becomes more virulent. How can this change in virulence most likely be described?  
 (A) as a behavioral adaptation (B) as a survival disadvantage (C) as a response to a stimulus (D) as an acquired characteristic
Output (English): C