In this English grammar item on reported speech, a sentence is given in direct speech about a stadium and winning a match. Out of the four alternatives, select the option that best expresses the same idea in indirect speech: They said, "This is the stadium where we had won the match."

Introduction / Context:
This question focuses on converting a direct speech sentence about a particular place and a past achievement into indirect speech. In direct speech, the speakers point to a stadium and state that it is the place where they had won a match. In indirect speech, we must report this statement from another point of view, changing tense and reference words appropriately. Mastering such transformations helps with both spoken and written English accuracy in exams and real communication.

Given Data / Assumptions:

• The reporting verb "said" is in the past tense.
• The quoted clause uses "this is" to refer to a specific stadium.
• The clause also contains a past perfect form "had won" and the pronoun "we".
• The word "this" is a demonstrative pronoun related to place and needs adjustment.
• The reported sentence must keep the idea that they had already won a match at that stadium.

Concept / Approach:
When the reporting verb is in the past, the present simple "is" normally changes to past simple "was" in reported speech. The demonstrative "this" also changes to "that", because the reporter is usually not standing at the same place at the same time. The past perfect "had won" already shows an action completed before another past point, so that form stays as it is. The first person plural "we" becomes "they" to match the subject of the reporting clause. We also remove the quotation marks and insert "that" to introduce the reported clause.

Step-by-Step Solution:
First, remove the comma and quotation marks and join the reporting clause and the reported clause with "that". Second, change the demonstrative "this" to "that" to reflect the new point of view in reported speech. Third, backshift the present simple "is" to "was" because the reporting verb "said" is in the past. Fourth, change the pronoun "we" to "they" so that it matches the subject "they" of the reporting clause. Fifth, keep the past perfect "had won" unchanged, since it is already correctly placed in the past relative to the time of saying.

Verification / Alternative check:
The resulting sentence "They said that that was the stadium where they had won the match" clearly reports a statement made earlier about a specific stadium. The structure shows that the reference to the stadium and the winning of the match are both in the past relative to the reporting. Reading the sentence aloud, you can see that it sounds natural and maintains the original meaning that the match had been won at that particular stadium before they spoke about it.

Why Other Options Are Wrong:
Option B changes "the match" to "that match", which is not strictly wrong but is unnecessary and less natural in this context. Options C and D keep the verb "is" in the present, which is incorrect after a past reporting verb "said". They also create a mismatch between the time of speaking and the time of reporting. Only option A correctly backshifts "is" to "was", changes "this" to "that", and keeps the past perfect form "had won" with the correct pronoun "they".

Common Pitfalls:
Many learners remember to change "this" to "that" but forget to backshift the present tense of the verb "to be". Others may over-edit by changing too many surrounding words, which can slightly alter the meaning. Some candidates also hesitate when they see two instances of "that" in a row, but in English it is completely acceptable to have "said that that was" when one "that" is a conjunction and the other is a demonstrative. Paying attention to function and meaning rather than appearance helps avoid these mistakes.

Final Answer:
The option that correctly converts the given direct sentence into reported speech is: They said that that was the stadium where they had won the match.