In the following English grammar question on reported speech, a sentence is given in Direct Speech: "They said, We will attend the performance tomorrow." Choose the option that correctly changes this sentence into Indirect Speech.

Introduction / Context:
This question tests your understanding of Direct and Indirect Speech in English grammar, specifically how to report a future action introduced by a past reporting verb. The original direct speech sentence is: They said, "We will attend the performance tomorrow." To choose the correct reported form, you must know how tense, pronouns and time expressions change when we move from direct to indirect speech.

Given Data / Assumptions:

- Reporting clause: They said. - Reported clause: We will attend the performance tomorrow. - Reporting verb said is in the past tense. - The word tomorrow refers to the day after the day of speaking.

Concept / Approach:
When the reporting verb is in the past tense, the tense in the reported clause generally shifts back one step. Future will usually changes to would. The first person plural pronoun we changes according to the subject of the reporting verb, here they, so we becomes they. Time expressions also change: tomorrow generally becomes the next day or the following day. The structure in indirect speech is: They said that plus reported clause with correct tense and time expression.

Step-by-Step Solution:

Verification / Alternative check:
To verify, convert the indirect sentence back into direct speech. Starting from They said that they would attend the performance the next day, change would attend back to will attend and the next day back to tomorrow. The sentence becomes They said, "We will attend the performance tomorrow." This matches the original direct sentence, so the transformation is correct.

Why Other Options Are Wrong:
Option A says the day after tomorrow, which wrongly adds an extra day and changes the time reference. Option B keeps will instead of changing it to would, and also uses the incomplete phrase the day after. Option D also keeps will, which is not acceptable when the reporting verb is in the past. Option E uses would be attending, which changes the simple future idea into a continuous aspect that is not necessary in standard reported speech for this sentence.

Common Pitfalls:
Students often forget to shift the tense of will to would when the reporting verb is in the past tense. Another common mistake is mishandling time expressions such as today, yesterday and tomorrow. Many learners also forget to adjust pronouns like we, which must reflect the viewpoint of the reporter in indirect speech. Remember that small changes in time expressions can change the meaning of the sentence if not done carefully.

Final Answer:
The correct indirect speech form is They said that they would attend the performance the next day.