Which electron configuration corresponds to a neutral oxygen atom (atomic number 8) in the simplified orbital notation?

• A. ${\mathrm{1s}}^2{\mathrm{2s}}^1{\mathrm{2p}}^5$
• B. ${\mathrm{1s}}^2{\mathrm{2s}}^2{\mathrm{2p}}^5$
• C. ${\mathrm{1s}}^2{\mathrm{2s}}^2{\mathrm{2p}}^4$
• D. ${\mathrm{1s}}^2{\mathrm{2s}}^2{\mathrm{2p}}^3$

Answer: (C)