Kemija - 2020. jesen, 2.

A. $\mathrm{O}\backslash mathrm\{O\}$

B. ${\mathrm{O}}^{2-}\backslash mathrm\{O\}^\{2-\}$

C. ${\mathrm{O}}_2\backslash mathrm\{O\}\_\{2\}$

D. ${\mathrm{O}}_2{}^{2-}\backslash mathrm\{O\}\_\{2\}\{\; \}^\{2-\}$