In this English grammar question, a sentence is given in direct speech about noise and disturbing the neighbours. Out of the four alternatives, select the option that best expresses the same idea in indirect or reported speech: My brother said, "I was not making a noise thus I did not disturb the neighbours."

Introduction / Context:
This question again tests reported speech, but here the focus is on a negative past continuous action and its result. In direct speech, the brother explains that he was not making a noise and therefore did not disturb the neighbours. In indirect speech, we need to show that both the continuous action and the result happened before the moment of reporting. Correct handling of tense backshift, linking words like "so" or "thus", and negative forms is essential for a fully correct answer.

Given Data / Assumptions:

• The reporting verb "said" is in the past tense.
• The quoted part contains a past continuous form "was not making" and a simple past form "did not disturb".
• The sentence contains a cause and effect connector "thus" or "so".
• The speaker is "my brother", so the first person "I" becomes "he" in reported speech.
• There are no time or place words that need to change, only tense and pronouns.

Concept / Approach:
With a past reporting verb, both the past continuous and the simple past inside the quotation are normally shifted one step back. "Was not making" becomes "had not been making", and "did not disturb" becomes "had not disturbed". The negative word "not" stays in place, and the connector "thus" or "so" continues to show cause and effect. Pronouns change in a logical way: "I" becomes "he". We also add "that" after "said" and remove comma and quotation marks. The final sentence must still clearly state that because he had not been making any noise, he had not disturbed the neighbours.

Step-by-Step Solution:
First, drop the comma and quotation marks and join the clauses with "that". Second, change "I" to "he" to refer to the brother and keep the negative idea "not making a noise". Third, backshift "was not making" to "had not been making" to show that the action happened before the time of reporting. Fourth, backshift "did not disturb" to "had not disturbed" and keep the link word "so" or "thus" to preserve the cause and effect relationship. Fifth, read the complete sentence to ensure that both actions now sit correctly in the past relative to the reporting verb and that the meaning is unchanged.

Verification / Alternative check:
The correct reported sentence should make it clear that at the time of speaking in the past, the brother had already not been making any noise and had already not disturbed anyone. "My brother said that he had not been making a noise so he had not disturbed the neighbours" satisfies this condition. Both clauses use the past perfect or past perfect continuous forms, which are appropriate after a past reporting verb. The negative forms are in the correct positions, and the logic of cause and effect remains intact.

Why Other Options Are Wrong:
Option A mixes past perfect continuous "had not been making" with a present perfect progressive idea "has not been disturbing", which clashes with the past reporting verb. Option B only partially backshifts, keeping "was not making", and therefore does not show that the action took place before the time of reporting. Option C contains a grammatical error because it omits the subject "he" before "was not making" and also uses the present perfect "has not disturbed". These problems make them incorrect as reported speech. Only option D applies the tense changes consistently and preserves the meaning.

Common Pitfalls:
Learners often fail to backshift all verbs when there is more than one clause inside the quotation. Another common problem is mixing past and present perfect forms in the same reported sentence, which leads to a confused time reference. Some students also omit or change the linking word "thus" or "so", which may weaken the cause and effect relationship. To avoid these mistakes, always identify each verb inside the quotation and shift all of them, while keeping connectors and negatives in the same logical positions.

Final Answer:
The option that correctly converts the given direct sentence into reported speech is: My brother said that he had not been making a noise so he had not disturbed the neighbours.