What is the best alignment definition for the Multiple Sequence Alignment (MSA) problem?
In your case both answers are equally valid.

The scoring matrix, for example DNAFULL (http://rosalind.info/glossary/dnafull/) usually contains various penalties for wrong alignments.

Also the introduce gap score should NEVER be set at 0 as it will cause the aligned sequences to be filled with artificial gaps!

The only thing the algoritms try to optimise towards is the score, therefore you need sane values for calculating the score and those you propose does not result in usefull alignments.