People who assume that no evil can befall them are foolishly complacent.

• Word: Complacent (adjective)

• English Meaning: Showing smug or uncritical satisfaction with oneself or one’s achievements.

• Bengali Meaning: আত্মতুষ্ট; পরিতৃপ্ত।

Meanings of the given options:

1. Ardent (adjective)

   • English Meaning: Very enthusiastic or passionate.

   • Bengali Meaning: অতিশয় আকুল বা অত্যন্ত উৎসাহী।

2. Confident (adjective)

   • English Meaning: Feeling or showing confidence in oneself or one’s abilities or qualities.

   • Bengali Meaning: আত্মবিশ্বাসী; আস্থাশীল; নিশ্চিত।

3. Apprehensive (adjective)

   • English Meaning: Anxious or fearful that something bad or unpleasant will happen.

   • Bengali Meaning: উদ্বিগ্ন; উৎকণ্ঠিত; শঙ্কিত।

Explanation:
In the given sentence, the word complacent is the most appropriate choice.
It refers to a state of self-satisfaction or false assurance, especially when one foolishly believes that nothing bad can happen to them, even when danger or wrongdoing is near.

Sources:

1. Oxford Learner’s Dictionary

2. Accessible Dictionary by Bangla Academy