Answer:
(A) $89.80; (B) $89.85
Explanation:
A) A market buy order would be filled instantly at the best offer price i.e. the sell order with the lowest price which will also be the sell order that is topmost on the order book.
As such, a market buy order for 125 shares will be filled at a price of $89.80.
B) The next market buy order would be filled at the next best offer price after the order in (A) above has been filled. Accordingly, the next market buy order will be filled instantly at $89.85.