The question asks an example for a MAJOR life change. Knowing this, we can eliminate you forget your homework and Your sister plays music loudly. Both of these choices may cause stress but they are not major life changes.
This leaves us with two possible answers: Your home is robbed or your parent's divorce. This is more of a matter of opinion and the situation. For example, your family may be living in poor conditions and when you get robbed you may lose a lot of valuable things.
However, on a more logical note, if you get robbed, you may report to the police or have your insurance cover for the items you lost.
This leaves to the last answer, Your Parents divorce. Your parents are the source of your valuables and if they divorced those valuables may not exist (meaning this answer is like getting robbed but worse) For your whole life or at least most it, your parents have always been there for you... both of them. When your parents divorce, you may move out of your school, town, house. You may be disconnected with your friends, siblings, family. Your life dramatically changes, making this one of the most stressful major life changes.
I would tell them to tell a trusted adult and use a helpline like nsvrc.org as a resource. Be there to support them during the aftermath as it will take a toll on their mental health.
