Three of them have been found, but one is still missing.
The Four Great Surfer Dudes all have boards that follow the same theme.
Which is the board they are looking for?
The patterns on the board of the Four Grea Surfer Dudes are all adaptations of an original design.
The patterns on the board look like waves, but they are actually certain shapes that have been cut in half and lined up.
The theme of the designs is card suits.
The board you are looking for is the one based on the suit of diamonds.
Answer for 'Surf's Up?'
The answer is 'C'.