The correct option that describes the structure of the electron shells in a neutral carbon atom is:
The inner shell is complete with two electrons. The outer shell is incomplete with four electrons.
In a neutral carbon atom (atomic number 6), there are 2 electrons in the first shell (which can hold up to 2 electrons), and 4 electrons in the second shell (which can hold up to 8 electrons, but in carbon’s case, it has 4, making it incomplete).