💡 Detailed Explanation
"潔く (isagiyoku)" describes an attitude of being straightforward and accepting a situation without lingering regret or excuses. It is the most suitable word for admitting one's mistake decisively. The other choices are incorrect: "潔白に (keppaku ni)" means "innocently," "清廉に (seiren ni)" means "with integrity/incorruptibly," and "果敢に (kakan ni)" means "boldly/daringly."