Approximate the complexity of the selection sort $($Algorithm $5\mathrm{.}21).$

$\backslash$Theta $(2$n$)$

$\backslash$Theta $($n$)$

$\backslash$Theta $($n$2)$

$\backslash$Theta $($n log$2$ n$)$

$\backslash$Theta $($log$2$ n$)$