Rug wrapped on a armchair is misinterpreted as bear

A 8 year old child after tonsillectomy sees a bear in her room. She screams in fright. A nurse who rushes in switches on the light, finds a rug wrapped on a armchair. She pacifies the child what the child experienced was a -

  1. Delusion

  2. Illusion

  3. Hallucination

  4. None of the above

Explanation

A real object, i.e. rug wrapped on a armchair is misinterpreted as bear.