What real-world issue is the author referring to by using a lifeboat metaphor in "lifeboat ethics: the case against the poor"?
a. starvation, in regard to how many people need food supplied by other countries in order to survive
b. racism, in regard to how many people use prejudice to decide who gets food and who doesn't
c. reproduction, in regard to how poorer nations have a much higher rate of population growth
d. foreign policy on immigration, in regard to how many people can live in a country and still preserve its resources