3
4
6
7
Answer is Wrong!
Answer is Right!
The correct answer is $\boxed{\text{C}}$.
The outermost orbit of an atom is called the valence shell. The number of electrons in the valence shell determines the chemical properties of the atom. Carbon has 6 electrons in its valence shell, which makes it a very reactive element. It can form four covalent bonds with other atoms, which is why it is found in so many different compounds.
Option A is incorrect because carbon has 6 electrons in its valence shell, not 3.
Option B is incorrect because carbon has 6 electrons in its valence shell, not 4.
Option D is incorrect because carbon has 6 electrons in its valence shell, not 7.