Part I: Run time Analysis Calculation

For each of the following code fragments calculate its runtime analysis and the $O(n)$

public void $m4($int $n$

${\displaystyle \underset{?}{\overset{?}{}}}=0$;

for$($int $)=0$;$k$

sum$++$;

$\{))=0$;$k$

sum$++$;

$\{(9)=0$;$j$

sum$++$;

$\{$

I need help with the runtime analysis. Thanks