Which of the following alternatives gives the correct form of indirect speech to the given sentence? She said to him, “Why do not you go today ?

The direct sentence is a wh-question (why), so the reported form must be a question introduced by asked, not said...that. The question word 'why' stays, the inverted 'do not you' becomes the statement order 'he did not go', and the tense shifts from present 'do' to past 'did'. The time word also changes: 'today' becomes 'that day' in reported speech, because the reporting is done on a different day.

Why the others fail:

• A keeps 'that why', retains 'donot' and never converts the question into a reported question.
• B drops 'why' and changes the question into a yes/no 'if' question with 'was going', which alters the meaning.
• C is structurally right but keeps 'today', which should be 'that day'.

Core concept: reported speech rules for questions (wh-question to asked + why + statement word order), tense backshift and deictic time words. This is a steady Prelims staple and a useful skill for Mains essay and precis writing.

Trap: aspirants pick C because it looks almost identical to D and ignore the 'today' to 'that day' change.