Answer:
A. new research on the harmful effects of pesticides
Explanation:
The "Environmental Protection Agency" (EPA) began operating in 1970 as a response to Rachel Carson's publication, Silent Spring. The publication tackled the harmful effects of pesticides to the environment. This alerted the public and such increasing concern was responded by the Congress.
Hearings were held and Nixon's proposal of an executive organization that would be in charge of environmental responsibilities was approved. They then introduced the Environmental Protection Agency. Many people became interested in the agency because it was meant to clean the air in America.
So, this explains the answer.