Having C's on some courses is not the end of the world, but I would recommend that you retake them if you have the time. With lots of shadowing and great extracurricular activities, I am sure that schools would know that you are able to complete a rigorous OD curriculum. However, they would be more inclined to choose an application with higher grades to be on the safer side. They want to make sure that all their selected students can successfully pass their programs and boards. I had a D on one of my classes and a couple of C's, so I retook some of those classes and I got interview offers from all schools that I applied to. The schools recognize when you put hard work and resilience into their applications, so retaking classes can only help you boost your chances. Good luck!
