the complexity of the following nested for loops is described best by which of the following choices?

int sum$=0$;

for$($int i$=1$;i$1$;j$=$j$/2)$

for$($int k$=$n$/2$;k$>1$;k$--)$

sum$++$;

options

O$($n$^2$ log n$)$

O$($log$^3$ n$)$

O$($n$^3)$

O$($n log$^2$ n$)$