Answer: (D) Code model
Step-by-step explanation:
The code model is the implementation of the particular system in the environment. The implantation of code model is basically the collection of the different components and subsystem together in the system.
The code model actually represent the database system and various software components. It is basically used to implement the elements in the coding or programming that is specifically implement in the program.
On the other hand, all the other options does not involve in the process of implementation of system. Therefore, option (D) is correct.