What is the real damage when a board is described as 'liquid-damaged'?

Select one answer.

• The wetness itself, which is entirely gone the moment the board has dried, leaving behind no lasting damage of any kind to repair.
• The corrosion the liquid starts, an ongoing attack that keeps eating metal and spreads after the board dries and the visible mess is wiped away.
• Only the cosmetic staining on the surface, which can always be polished off completely without any effect on how the board functions.
• A single mechanical crack formed at the very instant of the spill, which stays fixed in one place and never changes or spreads any further at all over time.