During the nineteenth century, occupational information

I just need to understand why is A not the correct answer here . It discusses methods ?


During the nineteenth century, occupational
information about women that was provided by the
United States census—a population count conducted
each decade—became more detailed and precise in
response to social changes. Through 1840, simple
enumeration by household mirrored a home-based
agricultural economy and hierarchical social order: the
head of the household (presumed male or absent) was
specified by name, whereas other household members
were only indicated by the total number of persons
counted in various categories, including occupational
categories. Like farms, most enterprises were familyrun,
so that the census measured economic activity as
an attribute of the entire household, rather than of
individuals.
The 1850 census, partly responding to antislavery and
women's rights movements, initiated the collection of
specific information about each individual in a
household. Not until 1870 was occupational
information analyzed by gender: the census
superintendent reported 1.8 million women employed
outside the home in "gainful and reputable
occupations." In addition, he arbitrarily attributed to
each family one woman "keeping house." Overlap
between the two groups was not calculated until 1890,
when the rapid entry of women into the paid labor
force and social issues arising from industrialization
were causing women's advocates and women
statisticians to press for more thorough and accurate
accounting of women's occupations and wages.

The primary purpose of the passage is to
(A) explain and critique the methods used by early
statisticians
(B) compare and contrast a historical situation with a
current-day one
(C) describe and explain a historical change
(D) discuss historical opposition to an established
institution
(E) trace the origin of a contemporary controversy