A customer has entered a day order to buy 500 shares of ABC stock at $21 on the NYSE. Later in the same day, the customer tells the broker to change the order to GTC. The registered representative should:
A.immediately cancel the old order and enter the new order
B.immediately enter the new order, leaving the old order undisturbed
C.wait till the end of the day, and if the existing order was not executed, enter the new order
D.enter a change order directing the Specialist/DMM to change the order duration
