I think it is A: It makes clear to the reader that the narrator is making an ironic statement.
People do change. Life experiences and maturity change people. If anyone thinks back to what he was like at eighteen and what he is like at thirty, it would be miracle if changes had not been made in his personality and behaviour.
There are so many events in a person's life that will alter his behaviour and even his/her way of looking at things: marriage, children, jobs, parents' deaths, money problems, divorce, health problems. All of these occurrences will alter the way a person acts and thinks.
Every stage of a person's life will bring different attitudes and changes in what a person does. Sometimes, the changes are for the better. There are instances when a person becomes bitter as he ages. As a person ages, his priorities change. Health issues move to the forefront. Health insurance and doctors become a part of life.
The point is that everyone changes as life events occur. No one stays the same.
