Consider the method below, which is intended to return true if there is at least one duplicate in the array, and false if there are no duplicates.

boolean hasDuplicate $($ int $[]$ nums$)$

$\{$

for $($ int k $=0$; k $<$ nums.length $-1$; k$++)$

$\{$

if $($nums $[$ k $]==$ nums $[$ k $+1])$

return true;

$\}$

return false;

$\}$

Under which condition will the method not necessarily produce the desired result?

a$.$

When the array is sorted in decreasing order.

b$.$

When the values in the array are all positive.

c$.$

When the values in the array are all the same.