The first option is most salient, by virtue of being first.

Level 0 players will tend to choose option 1. Level 1 players will realize that this is what level 0 players will do, so they will tend to choose option 2 ("the first one"). Level 2 players will realize that this is what level 1 players will do, so they will tend to choose option 4 ("the second one"). Level 3 players will realize that this is what level 2 players will do, so they will tend to choose option 5 ("the fourth one"). Apparently there are lots of level 1 & 2 players, but very few level 3 players.

But this analysis does not explain why so many people chose option 3 ("the last one") - I doubt that they are level 4 players. Perhaps it's that the last answer is the second-most-salient, by virtue of being last, making them level 1 players with a twist.