The correct answer is d) An era of negotiation.
When President Nixon took office, he announced that an "era of confrontation" in foreign policy would be replaced 'era of negotiation'
This was in reference to a time when the Cold war between the United States and the Soviet Union was raging all over the world.
There had been a huge build up nuclear and conventional weapons and billions spent all around the world where both countries had funded proxy warns and destroyed numerous countries.
Nixon hoped that the 'Cold War' could be brought to a gradual end through formal negotiations.