Find the number of electron(s) in O₂ molecule which is/are present in molecular orbital with given shape.

Antibonding orbital of the given shape are ${\left({\sigma }_{1s}^{\ast }\right)}^2\text{ and }{\left({\sigma }_{2s}^{\ast }\right)}^2$. Thus, the number of electron,

$$\begin{gathered} =2+2 \\ =4 \end{gathered}$$

Thus, the correct answer is 4.