Richard Nixon, authorized a bombing campaign against Cambodia, resulting in increased opposition to the war in Vietnam. Thus, option (c) is correct.
Nixon's decision to launch the Cambodian campaign was shown on television, sparking a wave of antiwar protests that erupted into a national crisis when four students were shot at a demonstration at Kent State University in Ohio.
Nixon had been covertly bombing Cambodia since the middle of March 1969, expanding a Johnson-initiated operation that had begun in 1965, but this fact was unknown to the public. Nixon gave the go-ahead for an American military "incursion" into Cambodia, ironically escalating the country's involvement in the long-stagnant war there while also aiming to end it.
Therefore, option (c) is correct.
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