Critical Reasoning

The education offered by junior colleges just after the Second World War had a tremendous practical effect on family-run businesses throughout the country. After learning new methods of marketing, finance, and accounting, the sons and daughters of merchants returned home, often to increase significantly the size of the family's enterprise or in other ways, to maximize the profits.

Which of the following statements is best supported by the information above?

A) The junior colleges principally emphasized methods of increasing the size of small businesses.
B) The business methods taught in the junior colleges were already widespread before the second World War.
C) The business curricula at junior colleges did not include theoretical principles of management.
D) Without the influence of junior colleges, many family-run businesses would have been abandoned as unprofitable.
E) Business methods in many post-war family-run businesses changed significantly as a result of the junior colleges.

OA: [[spoiler]b]E [/b][/spoiler]

I understand others answers are wrong..but can any one explain why Eis correct.
Major problem I see here is Business methods..