A marketing associate needs to import a CSV file into a data extension.

For importing a CSV (Comma-Separated Values) file into a data extension, the most appropriate delimiter is a comma. CSV files are structured with each data field separated by a comma, and each record is on a new line. When importing such files into Salesforce Marketing Cloud, selecting a comma as the delimiter ensures that the system correctly interprets the separation between individual data fields, allowing for accurate data mapping and importation into the specified data extension.