What is the runtime complexity notation for the following algorithm?

int lowNum$($int $[]$ listofNumbers, int listSize, int myAge$)\{$

for $($int $ctr=0$; ctr $$ listSize; $++$ctr$)\{$

if $($listOfAgeGroups$[$ctr$]==$ myAge$)$

return ctr

$\}$

$\}$

$\}$

$O(1)$

$O(N^2)$

$O(N*logN)$

$O(N)$