The correct answer is E. No correction required.
The sentence “Don’t forget to telephone me after you reach Delhi” is in the simple future tense. This means that the speaker is making a prediction about something that will happen in the future. In this case, the speaker is predicting that the listener will reach Delhi at some point in the future. The speaker is also asking the listener to call them after they reach Delhi.
The other options are all incorrect because they do not reflect the simple future tense. Option A, “shall reach,” is in the future tense, but it is the subjunctive mood. The subjunctive mood is used to express wishes, possibilities, or conditions that are not certain. In this case, the speaker is not expressing a wish or a possibility; they are making a prediction. Option B, “you have reached,” is in the past participle form. The past participle form is used to form perfect tenses. In this case, the speaker is not talking about something that has already happened; they are talking about something that will happen in the future. Option C, “would reach,” is in the
conditional mood. The conditional mood is used to express hypothetical situations or possibilities. In this case, the speaker is not expressing a hypothetical situation; they are making a prediction. Option D, “will have reached,” is in the future perfect tense. The future perfect tense is used to express something that will have happened by a certain point in the future. In this case, the speaker is not talking about something that will have happened by a certain point in the future; they are talking about something that will happen at some point in the future.