Suppose five boats are adrift at sea, each one containing a number of your relatives, and you have the power to save one boat from a dire fate. According to kin selection theory, it would be in the best interest of your genome to save a boat that contains .

one sister, one half-brother, and three cousins.

Explanation:

Kin selection theory also called inclusive fitness theory describes the self-sacrificial behaviour of organism, animal or individual to ensure survival of closely related family at the detriment of the individual's survival in order to preserve genetic fitness or survival and reproductive success of such individual. Therefore saving one sister, one half-brother, and three cousins will preserve the genetic lineage and reproductive success of the genome of interest