Four friends - Alex, Brian, Charlie, and David - have different favorite colors: Red, Blue, Green, and Yellow. Alex does not like Blue or Green. Brian likes Red. Charlie's favorite color is not Yellow. What is David's favorite color?
Answer: C. Green
Since Brian likes Red, and Alex does not like Blue or Green, Alex must like Yellow. Charlie cannot like Yellow, so he must like Green. Therefore, David's favorite color is Blue.