James could have been a classical musician if he’d continued his cello lessons.

A It was only because James stopped taking lessons on the cello that he was unable to become a classical musician.

B Originally, James had wanted to become a classical musician, and so he took cello lessons for a time.

C It was the cello lessons that he took for a long time that enabled James to become a classical musician.

D James never became a classical musician, but he did continue taking cello lessons nonetheless.