Final answer:
The statement supporting the claim that conservation is a collective responsibility is OC, reflecting a time when there was a collective effort to conserve resources under President Carter's leadership.
Step-by-step explanation:
To support the author's claim that "conservation is a collective responsibility," one must choose a statement that reflects the need for a united effort in the conservation of resources. The correct answer that supports this claim is OC: "The highest levels of conservation took place in the mid-to late 1970s when President Carter was asking citizens to be responsible for conserving resources." This statement illustrates a period when conservation was a priority and highlights the role of leadership and collective action in achieving conservation goals.