According to lazarus, our first task when faced with a potential stressor is to estimate its severity and to determine whether it is a challenge or threat. this evaluation is referred to as a primary appraisal secondary appraisal stress-related decision hassle-related decision

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.