Final answer:
Broker-dealers are required to file a report listing all written complaints with FINRA within 30 days of the end of each calendar quarter.
Step-by-step explanation:
The question pertains to the filing requirements for reports on written complaints with the Financial Industry Regulatory Authority (FINRA). Broker-dealers must file a report with FINRA that lists all customer written complaints within 30 days of the end of the calendar quarter. Therefore, the correct answer to the student's question is option 2) 'Within 30 days of the end of each calendar quarter.'