Answer: a. The national government instituted regulations to handle environmental issues.
The 1960s and 1970s were a period of increased awareness about environmental issues among the population. One of the catalysts was the book Silent Spring (1962) by Rachel Carson. The book discussed the negative effects of pesticides, in particular DDT, on wildlife. The 1969 Santa Barbara oil spill also generated public outrage. As a result, many regulations were passed in order to protect the environment. Moreover, those that already existed were reviewed and rewritten to make them more comprehensive.