Final answer:
The large portion of foreign-born residents of the United States work in service-producing and blue-collar sectors.
Step-by-step explanation:
The subject of this question is Social Studies. It is asking about a large portion of foreign-born residents in the United States and their characteristics.
According to the information provided, many recent immigrants in the United States end up working in service-producing and blue-collar sectors, such as restaurant and hotel work, lawn care, and janitorial work. This suggests that option a. - work in service-producing and blue-collar sectors - is the correct answer.
Therefore, the answer to the question is a. Work in service-producing and blue-collar sectors.