Which source is most likely an authority on the subject?

A) Dr. Vale, a pediatrician, discusses electrical circuitry on her home-improvement website.
B) Jonah, an amateur cook, teaches his son how to make the best grilled cheese sandwiches.
C) Susan, an architect, presents her hand-made quilts at the Quilting Society.
D) Dr. Patel, a cardiologist, presents her findings on heart disease.