After years of corruption, the politician suddenly started donating to charity, but most people dismissed it as an attempt to cover his tracks rather than a genuine change of heart.What does the underlined idiom mean?

Explanation

The idiom 'cover his tracks' means to hide or conceal one's wrongdoings, especially in a way that prevents others from discovering them. In the context of the question, it suggests that the politician's donations to charity are perceived as a way to distract from his past corrupt actions, rather than a sign of genuine change. The other options do not accurately reflect this meaning: 'To walk carefully' is a literal interpretation unrelated to ethics, 'To improve public image sincerely' implies honesty which is challenged by the context, and 'To protect others' suggests selflessness that does not fit the scenario presented.