2.3 Imagine you initially observe the sell portion of an order book as follows

Sell

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Price Size ID

20 1000 1

21 500 2

22 800 3

23 1200 4

An investor placed a buy order. Immediately after the order execution (assume no other orders have been submitted/executed), the same sell portion of the order book becomes

Sell

----------------------------

Price Size ID

21 500 2

22 800 3

23 1200 4

What kind(s) of order has this investor possibly submitted?

A. A market order.

B. A limit order.

C. A market-to-limit order.

D.A market-with-protection order.