According to the passage,which of the following is TRUE?
选项：

A: Freedman and his colleagues hired 400 000 Americans to collect data.
B:About four hundred thousand Americans worked for Freedman's team fall time for 13 years.
C:People who took part in Freedman's research are about 50 to 70 years old
D: People who are 50 to 70 years old seldom drink coffee.