The draft about the museum membership renewal contains several plausible insertion points. Paragraph 1: [1] A museum revised the message sent before an annual membership expired. [2] The new message listed the member's most-used benefit and the exact date access would end. Paragraph 2: [3] Renewals increased among members who had attended multiple special exhibitions. [4] Renewals changed little among members who had not visited during the year. [5] The draft then considers a different message for inactive members. Paragraph 3: [6] The writer concludes that relevance depends on prior experience, not personalization alone. The writer wants to add this explanation: "The contrast suggests that a personalized reminder was persuasive mainly when it recalled a benefit the member had actually used." At which location in the passage about the museum membership renewal does the sentence function as an explanation rather than as an unsupported claim?