"Come in, my friend", said I
বাক্যের সঠিক indirect speech :

প্রদত্ত বাক্যটিকে Direct থেকে Indirect করার নিয়ম: কাউকে Address বা সম্বোধন করা হলে বাক্যের শুরুতে Addressing as দ্বারা শুরু করতে হয়। কাজেই এক্ষেত্রে নিয়মটি হচ্ছে Addressing + যাকে সম্বোধন করা হয়েছে সেই nominal অংশের pronoun (এক্ষেত্রে him) + as + addressed অংশ (my friend) + Comma + Subject (I) + reporting verb say/said এর পরিবর্তে tell/told এক্ষেত্রে ‘told’ + object থাকলে (him) বসাতে হবে + বাকি অংশ বা extension (এক্ষেত্রে ‘to go in’) বসিয়ে এরূপ ‘assertive pattern’ এ রূপান্তর করতে হবে।

Out of the options provided, the most accurate indirect speech of the sentence "Come in, my friend," said I is:

Addressing him as my friend, I told him to go in.

Here's why:

• Reporting verb: Since the original sentence has "said I" in the first person singular past tense, we use "I told him" as the reporting verb in indirect speech.

• Reported speech: The direct speech "Come in, my friend" is converted to "to go in" in indirect speech, maintaining the meaning of the invitation but changing it into a reported infinitive clause.

• Preserving the address: The key point is that the indirect speech should capture the essence of the original communication, including the friendly address "my friend." Therefore, starting the sentence with "Addressing him as my friend" effectively incorporates the initial greeting into the narrative.

The other options are incorrect for the following reasons:

• Addressing him as my friend, he said him to go in: This changes the speaker from "I" to "he," making the reporting inaccurate.

• Addressing him as my friend, I have said him to go in: "Have said" is unnecessary in this context. In English, the present perfect tense is not typically used in reported speech unless there is a specific reason to emphasize the recentness of the event.

• Addressing him as my friend, I asked him to go in: While "asked" could be used in some contexts, "told" is a more neutral and direct way to convey the invitation in this case.