Pharmacists must know their job. If they did not know it, someone could easily die. . . . Interviewers will give you couple of questions about your studies, and they can even ask you some practical questions, to see whether you remember anything from school.
For your answer you should pick practical subjects and residency, as it shows that you like the real job of a pharmacist, and that you know what would be expected from you.
They know your marks
Each of us dislike some subjects. Interviewers have most likely seen your marks and know what troubled you the most at school. Therefore you should tell them about your weaknesses, and about subjects you struggled with. Nobody is perfect. Interviewers themselves had their problems with some subjects, and they will appreciate your honesty and humility.
I really enjoyed the APPE we had to complete. I had the chance to try a real job under supervision and I convinced myself once again that this is exactly what I want to do in my life. I believe it was a really good preparation for the job. And mathematical subjects, especially Calculus, were the toughest for me. It took me some time to pass the exam. I understood, however, that every subject is important, and I worked hard until I finally passed all the exams.