Which of the following responses best describes how member firms are required to retain electronic...

FINRA Rule 4511 requires member firms to retain records, including electronic communications, in a non-rewriteable, non-erasable format (often referred to as WORM: Write Once, Read Many). This ensures that records cannot be altered or deleted once stored.

D is correct because firms must store records in a tamper-proof format.

A, B, and C are incorrect because these formats do not guarantee compliance with the tamper-proof requirements set forth by FINRA and the SEC.