Correct Answer: He said that he would have to stay with her as her condition was critical.

Solution : The correct option is the third option .

When transforming a sentence from direct speech to reported speech, consider the following changes:

• Reporting Verb Change : "said" is changed to "said that" when reporting the speech.
• Pronoun Change : "I" is changed to "he" to reflect the change from the speaker's perspective to the reported perspective.
• Tense Change : The present tense "is" is changed to the past tense "was" in reported speech.
• Must is changed to "would have to".

Therefore, the indirect speech would be: "He said that he would have to stay with her as her condition was critical."