Here's a problem to solve: A teacher builds a model of a hydrogen atom. A red golf ball is used for a proton, and a green golf ball is used for an electron. Which is not accurate concerning the model?

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

- A: number of particles
 
- B: relative mass of particles
 
- C: types of particles present
 
- D: charges of particles present
 