Can anyone please help me understand the solution to this problem as the geeksforgeeks explanations is not clear to me especially this part

" In below code array numbers with remainder 0 and remainder K/2 are handled separately. If we include more than 2 numbers with remainder 0 then their sum will be divisible by K, so we have taken at max 1 number in our consideration, same is the case with array numbers giving remainder K/2. "