Final answer:
The middle class historically included professionals and skilled workers, but based on information provided, no single ethnic group from the options listed can be conclusively identified as predominantly making up the middle class.
Step-by-step explanation:
The composition of the middle class has been historically varied, shaped by cultural, economic, and geographic factors. Looking at the data provided, while Jewish people were found in all walks of life and could potentially be part of the middle class, it is not specified that they predominately constituted the middle-class population. The middle class would more typically consist of professionals and skilled workers such as managers, salesmen, engineers, doctors, accountants, etc. Additionally, specific groups, such as German and Irish immigrants, were often part of the middle class as they integrated into American life and became part of the established communities.
Responses based on the information given suggest that none of the ethnic options listed (Jewish, German, WASP, Italian) can be singled out as predominantly constituting the middle class without broader contextual information.