Modern atomic model

According to the modern atomic model, what is the electron configuration of $_{20}\ce{Ca}$ at the ground state?

(A) : $1s^2 2s^2 2p^4 3s^2 3p^4 3d^6$

(B) : $1s^2 2s^2 2p^6 3s^2 3p^8$

(C) : $1s^2 2s^2 2p^6 3s^2 3p^8$

(D) : $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2$