Final answer:
A penitent would most likely confess his sins, as it is the action that is aligned with expressing remorse and seeking to atone for wrongdoings.
Step-by-step explanation:
A penitent is someone who feels sorrow and regret for their wrongdoing or sins and often seeks to atone for them. Given the options provided, the action most aligned with being penitent is to confess his sins. This is because confession is an act of expressing remorse or guilt for one's actions, typically to a religious figure, as part of the process of seeking forgiveness. Cheating on an exam, buying a lottery ticket, and eating a big breakfast are not actions that reflect penitence, as they do not involve any acknowledgment of wrongdoing or an attempt to make amends.