Option 1 (flippant) -> means treating serious matters with casual disrespect, which contradicts his desire to make amends.
Option 2 (frivolous) -> means lacking seriousness or silly, which doesn't align with someone wanting to make up for their behavior.
Option 3 (apologetic) -> means feeling or expressing regret/remorse, which perfectly matches his intention to make amends by treating everyone.
Option 4 (impenitent) -> means showing no regret or shame, which is the opposite of someone wanting to make up for their actions.
Hence, Option 3 (apologetic) -> The word "apologetic" correctly describes someone who feels sorry for their rude behavior and actively wants to make amends, as indicated by the gesture of treating others at the ice cream parlour -> correct