I believe the final four are correct hope it helps :)
Answer:
a sunk cost, ( in economics) refers to the money spent and which cannot be recovered. for example: if you spent money on a game that you are interested in or on a game equipment in the game, the money cannot be recovered. Or in many games, there are things like diamonds, tickets etc which can be increased with real money, but after the usage, the diamonds or tickets get finished. It does not only finish those things but also your money, which gets spent but cannot be recovered. in a house, after the floor gets tiled, and if you hate that type of tile, you cannot return it back. here, the money gets spent and cannot be recovered.
Explanation:
