The correct answer is option (B):
Rainbow
The passage describes a political space filled with diverse ideologies. The best word to capture this concept of diversity is "rainbow." A rainbow is a visual representation of a spectrum of colors, each distinct but part of a unified whole. Similarly, a "rainbow" of ideologies implies a wide variety of political beliefs coexisting within the political landscape. The other options, "cluster," "parade," "horde," and "chain," do not accurately convey the idea of diverse ideologies. "Cluster" suggests a group, but not necessarily a variety. "Parade" implies a procession, not necessarily diverse ideologies. "Horde" denotes a large, disorganized group, which doesn't fit the context. "Chain" suggests a sequence, which doesn't accurately represent a spectrum of ideologies. Therefore, "rainbow" is the most appropriate word choice.