The best piece of evidence to support the argument for kin selection as a mechanism for the evolution of altruistic behavior would be "a penguin protects its chick from seagulls."
This example illustrates altruistic behavior where a parent (the penguin) protects its offspring (the chick), which is a direct example of kin selection. In kin selection, individuals are more likely to exhibit altruistic behaviors toward their relatives because it increases the chances of passing on shared genes to future generations. Therefore, protecting one's own offspring aligns closely with the principles of kin selection.