单项选择题

Questions 17 to 20 are based on the following passage. At the end of the passage, you will be given 20 seconds to answer the questions.
Now, listen to the passage.

Why has the dealer fixed the cards

A.Because be has an ace in the hole.
B.Because he is dealing off the bottom.
C.Because he can get higher cards.
D.Because the stacks are against him.