"I will finish the project," he promised. Which of the following is the correct direct speech for the given sentence?

 "I will finish the project," he promised. Which of the following is the correct direct speech for the given sentence?

•  "I will finish the project," he said. (Incorrect)
•  "I will finish the project," he declared. (Incorrect)
• "I will finish the project," he assured. (Incorrect)
•  "I will finish the project," he promised. (Correct)