What is the error message related to .class files?
A) The type .StringConcatFactory cannot be resolved. It is indirectly referenced from required .class files.
B) The type .StringConcatFactory cannot be instantiated. It is directly referenced from required .class files.
C) The type .StringConcatFactory cannot be resolved. It is directly referenced from required .class files.
D) The type .StringConcatFactory cannot be instantiated. It is indirectly referenced from required .class files.