What is output?

void doTheThing$($int a $[],$ int len$)$

$\{$

for $($int $i=1$; $i$ len; $i++)$

$a[i]=a[i]\%6$;

$\}$

$//**$ back in the main function

int arr$[]=\{10,20,30,40,50,60\}$;

int len $=6$;

doTheThing$($arr$,$len$)$;

cout $$ arr$[1]$ arr$[$len$-1]$;

a$)40$

b$)20$

c$)1050$