Answer:
Urban areas doubled, tripled, or quadrupled in size which led to over crowding in cities. Sometimes a large population is a good thing, but in this case the population was too big and caused many health problems.
Explanation:
I believe it's Option D.
Citizen journalism is essentially normal journalism, except most information used to write it is typically derived from other media like proffessional journalism.
B. By creating color contrast to focus on the mail ballerina.
