Step 1: Understanding the Question:
We are given a sentence in direct speech, "Suresh said, 'I did it yesterday.'" We need to convert it into indirect (reported) speech and pick the option that follows the correct grammar rules for this conversion.
Step 2: Key Formula or Approach:
Three things change when direct speech turns into indirect speech here.
First, the reporting verb "said" (with no listener named) stays "said", it does not change to "says" or "told".
Second, since the reporting verb is in the past tense, the verb inside the quote shifts one step back in time: simple past "did" becomes past perfect "had done".
Third, the pronoun "I" changes to match who is actually speaking from the narrator's point of view, so it becomes "he", and the time word "yesterday" changes to "the day before" because we are no longer speaking on the same day as the original statement.
Step 3: Detailed Explanation:
Applying these three changes to "I did it yesterday": "I" becomes "he", "did" (simple past) becomes "had done" (past perfect), and "yesterday" becomes "the day before".
Putting it together: "Suresh said that he had done it the day before."
Now check the wrong options.
Option (A), "Suresh said that I did it yesterday", keeps "I" and "yesterday" unchanged and does not shift the tense, so none of the three rules are applied.
Option (B), "Suresh says I did it yesterday", wrongly changes the reporting verb to the present tense "says", when the original was the past tense "said", and it also skips the tense shift and pronoun change.
Option (C), "Suresh says that he did it the day before", gets the pronoun and time word right but still wrongly uses "says" instead of "said", and fails to shift "did" to "had done".
Step 4: Final Answer:
Only option (D) applies all three rules correctly: reporting verb stays "said", the verb backshifts to "had done", and "yesterday" becomes "the day before". The correct answer is option (D).