Alan, Ben, Chris, Dave and Emma are eating a big cake, once again. After eating, there was one slice left, and they decided to leave it for Frank but someone ate it! Frank asks each person who ate the cake and they said:
Alan said: "It wasn't Ben. It was Chris."
Ben said: "It wasn't Alan. It was Dave."
Chris said: "It wasn't Dave. It wasn't Ben."
Dave said: It wasn't Emma. It was Alan."
Emma said: "It wasn't Chris. It was Dave."
If exactly 5 of the sentences are true, who ate the cake this time?!