Hi @eversm, we are looking for an answer choice that would guarantee that M and N are connected. You would be right that connecting J and O would guarantee this outcome. However, answer choice E does not say that J and O are connected, it only says that O is connected to one of J, K, or L. Since connecting O with Either K or L does not guarantee M and N are connected, answer choice E does not guarantee that they are connected. E is a could be true, and we are looking for a must be true.