Which statements about Java code security are true？（） 

• A、 The bytecode verifier loads all classes needed for the execution of a program.
• B、 Executing code is performed by the runtime interpreter.
• C、 At runtime the bytecodes are loaded， checked and run in an interpreter.
• D、 The class loader adds security by separating the namespaces for the classes of the local file system from those imported from network sources.