Here's a problem to solve: A researcher notices differences in the shapes of leaves on different trees of the same species. Which of these is the most accurate way to record these differences?

Among the 4 following options, which is the correct answer?

- A: record the numbers of leaves in a data table
 
- B: photograph each leaf type using a camera
 
- C: record the sizes of different leaves in a notebook
 
- D: calculate the percentages of all leaf types using a calculator
 