问题：

[单选]

A class games.cards.Poker is correctly defined in the jar file Poker.jar. 
A user wants to execute the main method of Poker on a UNIX system using the command： 
java games.cards.Poker 
What allows the user to do this？（） 

A .  put Poker.jar in directory /stuff/java， and set the CLASSPATH to include /stuff/java
B .  put Poker.jar in directory /stuff/java， and set the CLASSPATH to include /stuff/java/*.jar
C .  Put Poker.jar in directory /stuff/java， and set the CLASSPATH to include /stuff/java/Poker.jar
D .  put Poker.jar in directory /stuff/java/games/cards， and set the CLASSPATH to include /stuff/java
E .  put Poker.jar in directory /stuff/java/games/cards， and set the CLASSPATH to include /stuffijava/*.jar
F .  put Poker.jar in directory /stuff/java/games/cards， and set the CLASSPATH to include /stuff/java/Poker.jar