B
Carl is clearly an incompetent detective. He has solved a smaller percentage of the cases assigned to him in the last 3 years -- only 1 out of 25 -- than any other detective on the police force. Which one of the following, if true, most seriously weakens the argument above?
A: Before he became a detective, Carl was a neighborhood police officer and was highly respected by the residents of the neighborhood he patrolled.
B: Because the police chief regards Carl as the most capable detective, she assigns him only the most difficult cases, ones that others have failed to solve.
C: Carl was previously a detective in a police department in another city, and in the 4 years he spent there, he solved only 1 out of 30 crimes.
D: Many of the officers in the police department in which Carl serves were hired or promoted within the last 5 years.