Correct Answer & Explanation
Option D
• 'Touchstone' refers to a fundamental test or standard by which the value or quality of something is judged.
• 'Criterion' is the exact synonym meaning a standard or principle used in judgment.
• Other options: 'Discompose' means to embarrass/abash, 'Stigma' means a blemish/mark of disgrace, and 'Cupidity' means greed/covetousness.