The correct meaning of 'a man of letters' is-

- উল্লিখিত প্রশ্নে A man of letters শব্দের অর্থ হচ্ছে a male scholar or author.

• A man of letters
English Meaning: a male scholar or author.
Bangla Meaning: পণ্ডিত / বিদ্বান / লেখক
Ex. Sentence: Dr. Shahidullah was a man of letters.
Bangla Meaning: ড. শহীদুল্লাহ একজন পণ্ডিত / বিদ্বান ব্যক্তি ছিলেন।

Others Option & Meaning:
- 'Someone who has a weak character' is the meaning of A man of straw.
- 'An easy or defenseless target.' is the meaning of A sitting duck.
- 'An unreasonable or difficult demand' is the meaning of A tall order.

Source: Website Lecture.