What does Hamilton’s rule (rB> C) tell us?
A. When relatedness is low, benefit to the recipient is low, and cost to the actor is low, then natural selection should strongly favor individuals that help their kin. all options are correct
B. When relatedness is low, benefit to the recipient is high, and cost to the actor is high, natural selection should still favor individuals that help their kin.
C. When relatednessis high, benefit to the recipient is high, and cost to the actor is low, then natural selection should strongly favor individuals that help their kin.

The rule is based on the concept that our kin will also propagate our genes, but in proportion to our relatedness. So if the benefit is high (increasing the chances of our kin´s reproduction) and our cost is low (not reducing our chances of reproduction too much) the balance should favor that we take the action.

The action becomes less appealing as relatedness decreases. As someone said "I'd gladly die for two bothers or eight cousins"