Kannan said, "I wrote a letter".
AKannan said that he had written a letter
BKannan said that he has written a letter
CKannan said that he had been writing a letter
DKannan said that he wrote a letter
AKannan said that he had written a letter
BKannan said that he has written a letter
CKannan said that he had been writing a letter
DKannan said that he wrote a letter
Related Questions:
The teacher said to the students,"when did you get up yesterday?"
Change into Indirect speech