Which of the following is required BEFORE a registered representative can exercise discretion over a customer's account?

Why C — Written trading authorization (power of attorney) from the customer

Before exercising discretion, meaning the rep chooses the asset, action, or amount, the customer must provide written authorization, typically a limited power of attorney. Verbal authorization is not sufficient for discretionary authority. FINRA approval and minimum balances are not requirements for discretionary authorization. If the customer specifies the asset and action but lets the rep choose only the time or price, this is not considered discretion.