The correct answer is C. in.
An amateur is someone who does something for pleasure rather than as a job. Stenography is the practice of writing quickly by hand using a system of symbols. Therefore, Ali is an amateur in stenography because he does it for pleasure rather than as a job.
The other options are incorrect because they do not accurately describe Ali’s relationship to stenography. Option A, of, is incorrect because it suggests that Ali is a professional stenographer. Option B, for, is incorrect because it suggests that Ali is paid to do stenography. Option D, to, is incorrect because it suggests that Ali is learning stenography.