Postconventional level: In psychology, the term "postconventional level" is described as one of the three distinct levels in the moral development theory which was proposed by Lawrence Kohlberg.
According to Kohlberg, postconventional level is considered as the third and the last level of the theory whereby an individual tends to enter in the "highest level" of "morale development". At this stage, individuals are generally concerned with being guided by their "ethical principles or values" and knows the innate human rights.
In the question above, Kate is at the postconventional level of moral development in the given scenario.
The answer would be that stress rises from both the occurrences and our cognitive appraisal of them. Cognitive appraisal means that it is the personal understanding of a condition that eventually influences the degree to which the situation is professed as stressful.