Four friends - Alex, Ben, Clara, and Dana - play a card game where they each start with a different number of cards. During the game: Alex gives 3 cards to Ben Ben then gives 5 cards to Clara Clara then gives 2 cards to Dana After all exchanges, they discover that Alex and Clara now have the same number of cards After all exchanges, Ben has 12 cards Before any exchanges took place, Clara had 8 cards. Which one of the following statements must be true?