Correct Answer: The lawyer said that my case was very complicated.

Solution : The correct choice is the fourth option.

Indirect speech, also known as reported speech or indirect discourse, is a way of reporting what someone else has said without quoting their exact words.

The steps of conversion are as follows:

• There would be no change in the reporting verb.
• The auxiliary verb "is" would be changed to its past form, "was".
• The connector "that" is used to introduce the reported clause.

Therefore, the correct sentence is: "The lawyer said that my case was very complicated."