Select the correct indirect form of the given sentence.

Mother said, “All the guests will arrive tonight.”

Mother said that all the guests would arrive that night.

The correct indirect form of the given sentence is:

Mother said that all the guests would arrive that night.

The other options are incorrect:

• Mother said that all the guests will arrive tonight. This is incorrect because the tense of the reported speech is in the present tense, but the event is in the future.
• Mother said that all the guests will arrive that night. This is incorrect because the reported speech is in the present tense, but the event is in the future.
• Mother said that all the guests would arrive tonight. This is incorrect because the modal verb "would" should be used to express a future event that is not certain.