Most only children have a self-centered tendency. Some non-only children also have a self-centered tendency. There are various reasons for the self-centered tendency, but one common reason is the lack of proper parental guidance. If the above is true, which of the following must be true? ? ['Every family without proper parental guidance has only children.', 'Some parents lack the right guidance to guide their children as non-only children.', 'Although some families lack proper parental guidance, their children are not self-centered.', 'Most families lacking proper parental guidance have only children.']