A team of three is to be formed from the following people: Alex, Brian, Clara, and Diana. The selection rules are: 1) Alex and Brian cannot be selected together. 2) Clara must be included if Diana is included. Which of the following teams is valid?
Five people are standing in a line: Alex, Brian, Charlie, David, and Ethan. Alex is in front of Brian but behind Charlie. David is behind Ethan but in front of Brian. Who is in the middle of the line?