The correct answer is A, as the Progressive Era was a period in which many social reforms occurred.
The Progressive Era is the name given to a period in US history from the 1890s to the 1920s, although it is sometimes more restrictively associated with Theodore Roosevelt's presidency years (1901-1909).
It was an era in partial rupture with the laissez-faire and individualism of the previous period, marked by economic, political, social and moral reforms in response to the changes and problems brought about by the industrial revolution: the disappearance of a social life organized around small communities, instability resulting from the anarchic development of industry, commerce, business, big cities, agriculture, massive immigration from the south and east of Europe, escalation of the violence of social conflicts and upheavals caused by technological progress.
