Final answer:
The correct punctuation in the provided sentence is to keep the comma after 'WARD' (Option 3, no change) because it is part of a serial list and does not require a semicolon or period for separation.
Step-by-step explanation:
The student's question concerns the correct use of punctuation when listing individuals in a sentence. The part of the sentence in question lists pioneers in mail-order retail, "Aaron Montgomery Ward, Richard Sears, and Alvah Curtis Roebuck."
Option 1, replacing the comma after 'WARD' with a semicolon, is incorrect as semicolons are generally used to separate items in a list where the items themselves contain commas, or to separate closely linked independent clauses.
Option 2, replacing the comma after 'WOOLWORTH' with a semicolon, creates separation between the leaders in brick-and-mortar and their counterparts in mail-order retail. However, as these are separate and complete thoughts that could stand alone as independent sentences, a period might be more appropriate than a semicolon. That said, in the context of this sentence's flow and structure,
Option 3 (no change), is correct because the list that follows 'WARD' is simply a continuation of a series and does not require a semicolon or period.