The correct answer is: A. He said that he would go the next day.
The sentence “I shall go tomorrow” is in the simple future tense. In this tense, the verb “go” is conjugated to the first person singular form, “shall.” This form is used to express intention or determination. In this case, the speaker is expressing their intention to go somewhere on the next day.
The other options are incorrect because they do not accurately reflect the meaning of the sentence. Option B, “He said that he should go tomorrow,” uses the modal verb “should.” This verb is used to express obligation or recommendation. In this case, the speaker is not expressing an obligation or recommendation, but rather their intention. Option C, “He said that he would go tomorrow,” is the same as option A, but it uses the past tense form of the verb “go.” This form is not appropriate in this context, as the speaker is talking about something that they will do in the future. Option D, “He said that he shall go the next day,” is the same as option A, but it uses the emphatic form of the verb “go.” This form is not necessary in this context, as the speaker is already expressing their intention clearly.