The correct answer is primary appraisal.
According to Lazarus's theory of stress, primary appraisal refers to the process wherein individuals form a judgement or an evaluation of a stressor (an external factor or stimulus that can potentially cause stress) when they are first faced with it. Individuals might either evaluate and judge the stressor as being either a challenge or threat. For instance, if you notice that someone has been following you for a few blocks, through the process of primary appraisal you will determine whether or not its a threat.
