Final answer:
About half of all Americans have ancestors who immigrated through Ellis Island, suggesting a ratio close to 1 to 1 of people who can identify an Ellis Island immigrant relative to those who cannot.
Step-by-step explanation:
The question asks about the ratio of people who can identify that a relative came to the United States through Ellis Island compared to those who cannot. Given the historical context provided, it is known that nearly half of all Americans have ancestors who entered the country through Ellis Island. Therefore, the ratio would be close to 1 to 1 (option 'B. 1 to 2' might be the best approximation from the given choices, although '1 to 1' would be even more accurate). However, please note that the exact ratio could vary and the provided options may not fully reflect the precise historical data.