Answer: paying for order flow and hence must be allowed to do it so far he or she is subjected to the best execution requirements.
Step-by-step explanation:
A market maker that compensates a retail member firm for sending its customer orders to that market maker is paying for order flow and hence must be allowed to do it so far he or she is subjected to the best execution requirements.
It should be noted that in this scenario, the retail firm earns the payment for order flow and this is allowed by the Securities exchange commission as long as the best available price is allowed for the trade.