Which of the following statements about declaration are true？（）         

A、 Declaration of primitive types such as boolean， byte and so on does not allocate memory space for the variable.

B、 Declaration of primitive types such as boolean， byte and so on allocates memory space for the variable.

C、 Declaration of nonprimitive types such as String， Vector and so on does not allocate memory space for the object.

D、 Declaration of nonprimitive types such as String， Vector ans so on allocates memory space for the object.