The correct indirect speech of: "The old man said, 'Necessity knows no law.' " is –

The correct answer is - খ) The old man said that necessity knows no law.

- Reported speech যদি কোন চিরন্তন সত্য (universal truth) বা অভ্যাসগত সত্য (habitual fact) প্রকাশ করে তাহলে reporting verb-এর tense যাই না কেন, reported speech-এর verb-এর tense-এর কোন পরিবর্তন হবে না।
• Examples:
- Dir: The old man said, "Necessity knows no law."
- Ind: The old man said that necessity knows no law. (necessity knows no law = প্রয়োজন কোন আইন মানে না।)

- Dir: Mina said, "Every day I read newspapers.
- Ind: Mina said that every day she reads newspapers.
এখানে read-verbটি একটি অভ্যাসগত সত্য বুঝাচ্ছে যা Mina প্রতিদিন করে থাকে। speech-এ verb টির tense-এর কোন পরিবর্তন হয়নি; present সুতরাং indirect indefinite-ই রয়েছে।

- Dir: The teacher said, "The earth moves round the sun."
- Ind: The teacher said that the earth moves round the sun (universal truth বুঝাচ্ছে।)

- Dir: He said, "Every mother loves her children."
- Ind: He said that every mother loves her children.

- Dir: The professor said, "A hungry man wants food."
- Ind: The professor said that a hungry man wants food.

Source: A Passage To The English Language. S. M. Zakir Hussain.