Answer: Extinction
Explanation: Extinction simply means cessation. A condition whereby an action or behavior exhibited by an individual or organism eventually stops. In psychological parlance, extinction is usually attributed to the discontinuance of a certain behavior usually due to non - reinforcement or eventual absence of the conditioned stimulus.
In the scenario above, the point at which Mary stopped sneezing is called extinction which is due to the removal of the cat which is the cause of Mary's sneezing behavior.