You are correct my friend and the answer given in the book is also correct, i think you misinterpreted the answer. the following line:
"When javac is invoked with a classpath option, and you need to find files in a JAR file, the name of the JAR file must be included at the end of the path."
means that when you specify the -cp option, for eg:
now the above line has two class paths: 1) dirC/C.jar & 2) dirB A.java. the 1st classpath has a C.jar at the end of the path and if you remove it, the C.jar won't be searched for any files. so, the answer statement is not talking about the order in which class paths 1) and 2) are specified.