In the following question on Direct and Indirect speech, choose the reported form of the sentence: Manoj said, I must go now.

Introduction / Context:
This question checks knowledge of Direct and Indirect (reported) speech. The original sentence Manoj said, I must go now is in direct speech. The task is to express it in indirect speech while maintaining correct tense, pronoun, and time reference. Many competitive exams include such questions, because they test understanding of how spoken words are reported later by another person. Correct reporting involves changes in pronouns, time adverbs such as now or today, and sometimes modal verbs depending on the context.

Given Data / Assumptions:

• Direct speech: Manoj said, I must go now.
• Reporting verb: said.
• Reported clause: I must go now.
• We need a grammatically correct indirect sentence that preserves meaning.
• The reporting verb is in past tense, so normal rules of backshifting may apply, but modal must can remain must in many contexts.

Concept / Approach:
When changing from direct to indirect speech, we usually remove quotation marks and introduce a conjunction such as that. Pronouns change according to the subject of the reporting verb. Here, I refers to Manoj, so it becomes he in indirect speech. The time adverb now should shift to then because the reporting is done at a later point. The modal must can remain must when it expresses a general necessity or obligation at the time referred to, although in some contexts it can become had to. Among the options, the sentence Manoj said that he must go then correctly applies these changes without introducing spelling errors or tense mistakes.

Step-by-Step Solution:

Verification / Alternative check:
Check each option for both grammar and spelling. Option A, Manoj said that he must go then, is free of errors and follows standard rules for pronoun and time shift. Option B uses than instead of then, which is a spelling mistake, because than is used for comparison, not time reference. Option C changes must to has to and leaves out that, which might be acceptable in some spoken contexts but shifts the nuance of necessity and mix tenses, since said is past and has to is present. Option D combines should be going than, which is awkward and again misspells then. Therefore, option A is the best and most correct answer for standard written English.

Why Other Options Are Wrong:

• Option B is incorrect due to the misuse of than where then is required. This confuses comparison with time reference.
• Option C alters the modal from must to has to and uses a present tense auxiliary with a past reporting verb, which is not ideal for formal indirect speech in exams.
• Option D introduces should be going and again uses than, resulting in both a grammatical and spelling problem that changes the meaning and tone of the sentence.

Common Pitfalls:
Learners often confuse the words then and than, especially in speech where they sound similar for some speakers. Another pitfall is to change modals like must into should or has to without checking whether the strength of obligation is preserved. For exam purposes, it is safer to keep must as must when it expresses strong necessity at the time of speaking. Careful reading and attention to spelling are crucial in such questions, because even a small mistake like than instead of then can make an otherwise correct sentence unacceptable.

Final Answer:
Manoj said that he must go then.