Hich sentence from the passage best illustrates hardin's central argument?
a. and since the world's resources are dwindling, the difference in
prosperity between the rich and the poor can only increase.
b. put differently, the doubling time for this aggregate population is
21 years, compared to 87 years for the u. s.
c. the harsh ethics of the lifeboat become even harsher when we
consider the reproductive differences between the rich nations
and the poor nations.
d. outside our lifeboat, let us imagine another 210 million people
(say the combined populations of colombia, ecuador, venezuela,
morocco, pakistan, thailand and the philippines) who are
increasing at a rate of 3.3 percent per year.