Option 4 is the right answer. Let us look into the meaning of the given words:
Escape: break free from confinement.
Room: has walls, ceilings, floors, and doors, and is usually used for activities like storing/ sleeping etc.
Link: a connection between two people, things, or ideas.
Outlet: a pipe or hole through which water or gas may escape.
The given sentence is about water flowing. So, the obvious word for the blank is --'outlet' Complete sentence: There is no outlet in the container for the water to flow.