Verónica (2017 Spanish film) ending explanation

Question

In the movie Verónica (2017 Spanish film) there can be different explanations,

1. She was crazy and imagined things.
2. She was possessed by a ghost.
3. She was not possessed and there was another ghost.

Only Veronica sees and hears the ghost and things like that. At the end she remembers things like moving the glass in the Ouija board by herself, choking her sister, and closing door by herself.

So how should the movie be interpreted, especially the ending scenes ?

Answer 1

Lots of ghost movies go like this: the only people that see the ghost die, so no one else can be sure of what happened (like the Nightmare on Elm Street franchise).

The story is supposedly inspired by real events in the Valleca's case.

So I'd say this one is open to your own interpretation.