Answer:
The answer would be removing the electron. (D)
Step-by-step explanation:
The number of protons an element has determines which element it is. Carbons atomic number for example is 6 because it has 6 protons. When there are more electrons then protons it becomes an ion and if there are more neutrons then the element should normally have it is called an isotope. So in the "electron model" it would be removing the electron.