Aid-giving behaviour between genetically related individuals in animal groups is often observed in nature. This aid-giving behaviour can evolve when the advantages of helping relatives are greater than losses the aid-giver incurs in terms of not having its own offspring. This rule is called as Hamilton's rule and is given as rB > C, where r is genetic relatedness of the aid-giver and aid-receiver, B is benefit and C is cost.
If an individual is faced with an alternative of rearing its own offspring or rearing its cousin's offspring, what is the smallest amount number of offspring its cousin should produce so that helping will be favoured?
a. 2
b. 3
c. 4
d. 5