What is the cause of the error message?

Given the error message when running you application:
Exception in thread main java.util.MissingResourceException: cant find bundle for base name messageBundle, Locale

And given that the Message Bundle.properties file has been created, exists on your disk, and is properly formatted.
What is the cause of the error message?

A.
The file is not in the environment PATH.

B.
The file is not in the CLASSPATH.

C.
The file is not in the JJAVAPATH.

D.
You cannot use a file to store a ResourceBundle.

Explanation:
Your language file should be in the classpath.