In MLA documentation, to signify a quotation within a quotation, writers must:

A. use single quotation marks: "'I don't know,' Al said. 'I don't know what I want to eat'" (Hemingway 21).
B. use parentheses: "(I don't know,) Al said. (I don't know what I want to eat)" (Hemingway 21).
C. use asterisks: "*I don't know,* Al said. *I don't know what I want to eat*" (Hemingway 21).
D. use brackets: "[I don't know,] Al said. [I don't know what I want to eat]" (Hemingway 21).

I believe it is A, because that is what I mostly do and every other option seems silly to use.

you may need to add a question, yeah?

the service industry in the united states grew in the late 1800s. what was one effect of that growth?

the number of people with jobs in factories as unskilled workers decreased.

the number of people with jobs in factories as unskilled workers increased.

the middle class grew as people took jobs as clerks, lawyers, and teachers.

the middle class shrank as people left jobs as clerks, lawyers, and teachers.