Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
Ceylon had been independent for 24 years. Then its name was changed to Sri Lanka.
A.Ceylon had been independent for 24 years after its name was changed to Sri Lanka
B.Ceylon was independent 24 years ago when its name was changed to Sri Lanka
C.By the time Ceylon was independent for 24 years, its name had been changed to Sri Lanka
D.After Ceylon had been independent for 24 years, its name was changed to Sri Lanka