Correct Answer: She regretted that they had missed the flight.

Solution : The correct choice is the fourth option.

Narration Conversion:

• The first-person I is changed to the third-person pronoun she .
• The verb said is changed to the verb regretted since it is a case of regret.
• That is used to introduce the reported clause.
• The pronoun we is changed to they in the reported speech.
• The present perfect tense (have missed) is changed to the past perfect tense (had missed) .

Therefore, the correct sentence is: She regretted that they had missed the flight.