In the United States, Average Life Expectancy

In the United States, average life expectancy

A) is likely to continue to increase at the same rate it did in the early parts of the 20^th century
B) increased more rapidly between 1950 and 1999 than it did between 1900 and 1950
C) increased throughout the twentieth century primarily due to advances in medical technology
D) all of these
E) none of these