Aufbau principle is obeyed in which of the following electronic configurations [AFMC 1999]

• A.                 \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}\]             
• B.                 \[1{{s}^{2}}3{{p}^{3}}3{{s}^{2}}\]
• C.                 \[1{{s}^{2}}3{{s}^{2}}3{{p}^{6}}\]             
• D.                 \[1{{s}^{2}}2{{s}^{2}}3{{s}^{2}}\]