Final answer:
The Vicario twins believe their killing was an act of honor that should exempt them from punishment.
Step-by-step explanation:
The Vicario twins defend their killing and believe it was honorable based on the belief that it was an act of honor and should exempt them from punishment (Option 4).
They view their act as a way to restore their family's honor, as their sister had been wronged and they believed it was their duty to avenge her.
In their cultural context, this act was seen as an honorable way to restore lost honor.