What allows the user to do this?

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 /stuff/java/*.jar

F.
put Poker.jar in directory /stuff/java/games/cards, and set the CLASSPATH to include /stuff/java/Poker.jar

Explanation: