public int findLast $($int$[]$ x$,$ int y$)\{$

$//$Effects: If x$==$null throw NullPointerException

$//$ else return the index of the last element

$//$ in x that equals y$.$

$//$ If no such element exists, return $-1$

for $($int i$=$x$.$length$-1$; i $>0$; i$--)$

$\{$

if $(\}\backslash$textrm$\{$x$\}[\backslash$textrm$\{$i$\}]=\backslash$textrm$\{$y$\}$

$\{$

return i;

$\}$

$\}$

return $-1$;

$\}$

$//$ test: x$=[2,3,5]$; y$=2$

$//$ Expected $=0$

Which test case does not execute the fault?

a$)$ x $=$ null, y $=7$

b$)$ x $=[2,4,5],$ y $=3$

c$)$ x $=[2,4,3],$ y $=3$

d$)$ x $=[0,0,0],$ y $=1$