Answer:
A) Ruth, a member of the working poor living in Harlem.
Explanation:
Ruth would be the person who would most struggle when it comes to finding "elegible" marriage partners. In our society, there is an expectation that people marry within their social circle. This means that partners tend to have similiar socio-economic characteristics. Based on this, we can assume that Ruth's possible partners would most likely come from a poor background, and might not have the resources to get married, as a partner usually needs financial stability in order to be considered "elegible." Therefore, she is likely to have few possibilities of finding a partner.