What element has a symbol O?

We must keep in mind that the periodic table's atomic elements are represented by the atomic symbol. Certain groupings and eras make up periodic tables. And according to a periodic chart, the element with the atomic symbol O is a member of group 16. Charges on a certain element or atom are described as losing and gaining electrons.

This is a bad choice since the atomic symbol for cobalt, Co, has an atomic number of 27.
This element is a transition metal and is in the d block of elements.

Electronic configuration of $Co:\left[Ar\right]3d^{7}4s^2$

Option B) This is a correct option as$$O$$ this symbol is an atomic symbol of oxygen having atomic number 8. It belongs to group 16 in a periodic table.

Electronic configuration of: $O:1s^{2}2s^{2}2p^4$

O to complete its octet or reach a stable noble gas form, needs 2 fewer electrons. Oxygen gas has no smell and no colour. Water is produced when oxygen and hydrogen react. In the atmosphere of the earth, it makes up 21%. The oxygen oxidation states 1 and 2 are the most prevalent.

Oxygen also has isotopes i.e. $O^{16}{O}^{17}{{}^{17},}^{18}$

Hence, option B is correct.