In the following question, a sentence is given in Direct speech. Choose the option that best expresses the same idea in Indirect or reported speech. He told me, "Your train will leave if you do not go at once."

Introduction / Context:
This question tests the conversion of a conditional sentence from Direct to Indirect speech. The speaker warns the listener that the listener's train will depart if the listener does not leave immediately. The challenge is to preserve the conditional meaning while adjusting pronouns, tense, and time expression from Direct to reported form.

Given Data / Assumptions:

• Direct speech: He told me, "Your train will leave if you do not go at once."
• The reporting verb "told" is in the past tense and has the object "me".
• The main clause of the condition is "Your train will leave".
• The if clause is "if you do not go at once".
• "Your" and "you" refer to the listener who is "me" in the reporting clause, and "at once" expresses immediacy.

Concept / Approach:
In Indirect speech with a past reporting verb, simple future "will" changes to "would". Simple present in the if clause usually changes to simple past. Pronouns and possessives must be adjusted so that "your" becomes "my" and "you" becomes "I". The time expression "at once" can be reported as "that moment" or "immediately" depending on exam style, and here the option uses "that moment". The structure of the conditional sentence itself remains the same: "would leave if I did not go that moment".

Step-by-Step Solution:

Verification / Alternative check:
The reported sentence clearly shows the same conditional warning. The main clause uses "would leave" correctly as the reported version of "will leave". The if clause has the past form "did not go", and the pronouns now match the new point of view. The urgency expressed by "at once" remains present through "that moment". The message about the risk of missing the train is fully preserved.

Why Other Options Are Wrong:
Option A confuses pronouns by using "his train" and "he" instead of "my train" and "I", which changes the meaning. Option B keeps "will leave" and "do not go", breaking the backshift rule for Indirect speech. Option C again uses "his train" and "he", which does not match the original message where the warning is about the listener's train. Only option D correctly handles pronouns, tense backshift, and the time expression in a standard way.

Common Pitfalls:
Conditional sentences in reported speech are often tricky because they involve two clauses that may need tense changes. Learners sometimes change only the main clause and forget the if clause, or they incorrectly alter the structure of the condition. Pronoun changes also cause confusion when the sentence contains both "your" and "you". Carefully mapping each pronoun and verb to the new point of view is essential for accuracy.

Final Answer:
The correct Indirect speech form is He told me that my train would leave if I did not go that moment.