Altruistic behaviors can be understood, in part, by considering the coefficient of relatedness (r) between the individuals involved. Assume that an individual mammal has the option to raise its own offspring, other genetic relatives, or a combination of offspring and other genetic relatives. From a genetic point of view, which of the following represents the least successful option?

• A. Two offspring
• B. Two offspring and two first cousins
• C. Four grandchildren
• D. One sibling and three nephews
• E. Seven first cousins