They believed that this was not the ________ of their campaign for equality but merely the beginning.
句意：他们相信这并不是争取平等运动的高潮，而仅仅是个开端。climax高潮，顶点。summit 顶峰，顶点，指最高处、成就的顶峰。minimum最小值。maximum最大值。故选A。