It is no accident that Chapter 4 in the book has the largest number of figures of any of the chapters we have covered. This fact testifies to the power of diagrams to help organize and explain the physical concepts at the heart of understanding the cyclone. It would be a VERY GOOD IDEA to really understand the diagrams in Chapter 4 and the physical ideas that underlie them as you prepare for the final exam. Thus, the correct answer here is (d).