In terms of fitness, how is a "selfish" behavior characterized?

Selfish behavior in the context of evolutionary biology is characterized by actions that benefit the individual performing the behavior (the actor) while potentially causing harm to another individual (the recipient). This type of behavior is often seen in scenarios where one individual seeks to maximize its own reproductive success or resource acquisition at the expense of others.

In this sense, the selfish act increases the actor's fitness—defined as the ability to survive and reproduce—because the actor gains an advantage (such as resources, mates, or survival benefits) while the recipient may face a disadvantage (like loss of resources or decreased reproductive chances). This dynamic is central to understanding various interactions within ecology and evolutionary theory, including concepts like natural selection and competition.

The other options describe different types of interactions: mutual benefit (where both parties gain), neutrality (where neither is affected), or cooperative behavior (which enhances the welfare of both individuals). However, in selfish behavior, the focus is on the actor improving its situation at the potential cost to the other individual, which directly aligns with the definition of option B.