Which of the following modifications do not need to be made to transform the global alignment algorithm in the local alignment algorithm?

1. Initialize with zero the first column and the first row of the matrix.
2. Stop the reconstruction of a local alignment when it finds an 0 in the matrix.
3. Do not let the matrix values become negative; if the maximum value is negative, should be replaced by 0.
4. Find the highest value of the entire matrix to obtain the similarity and to use as a starting point for reconstruction of an optimal alignment.
5. None of the above.

Original idea by: Filipe Benevides Netto
Translation help by: Leandro José de Bortoli.