Answer: Match buy orders to sell orders.

The **order matching rules** in order-driven trading systems are designed to match buy orders to sell orders, ensuring trades are executed efficiently. - **Option B** is incorrect because the **trade pricing rules**, not the order matching rules, determine the prices at which matched trades occur, regardless of whether the orders are submitted by dealers. - **Option C** is also incorrect for the same reason as Option B; the trade pricing rules handle the pricing of matched trades, irrespective of whether the orders are submitted by customers.

Author: LeetQuiz Editorial Team