Did each country affected by the flu suffer the same death rate? If not, what probably accounted for the differences? Did different groups in the same place suffer the same fates?

In the last five camps affected—on average 3 weeks later—only 7.1 percent of influenza victims developed pneumonia. ... But in those same places, the people struck by influenza later in the epidemic were not becoming as ill, and were not dying at the same rate, as those struck in the first 2 to 3 weeks.

Explanation:

1.d 2.a c.!