I started training to be an accountant six months ago. I’ve got more months to go and then I have to take exams.

A. By the time I’ve taken my exam, I will have started training to be an accountant for a year.

B. By the time I take my exam, I will have been in training to be an accountant for a year.

C. By the time I took my exam, I would have trained to be an accountant for a year.

D. By the time I’ve taken my exam, I will be training for a year.