Correct Answer: modest

Solution : The correct choice is the fourth option.

Explanation: "Modest" is the opposite of "impudent". Impudence refers to a lack of respect or rudeness, while modesty refers to having or showing a moderate or humble estimate of one's merits, abilities, importance, or value.

The meanings of the other options are as follows:

• Arrant means complete or utter.
• Brazen means bold or shameless.
• Blatant means obvious or conspicuous.

Therefore, the correct answer is modest.