Which of the following electronic configurations is not possible [CPMT 2000]

• A.                 \[1{{s}^{2}}\,\,2{{s}^{2}}\]          
• B.                 \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}\]
• C.                 \[3{{d}^{10}}4{{s}^{2}}4{{p}^{2}}\]          
• D.                 \[1{{s}^{2}}2{{s}^{2}}\,2{{p}^{2}}3{{s}^{1}}\]