To understand what prevents this procedure from being created successfully, we need to examine the given procedure. The procedure DELETE_PLAYER takes an input parameter V_IDIN and attempts to delete the corresponding record from the PLAYER table. It also has an exception block that handles the STATS_EXIST_EXCEPTION exception and outputs an error message.

Now, let's go through each option and see if it affects the creation of the procedure:

A. a) A comma has been left after the STATS_EXIST_EXCEPTION exception. This option is incorrect. There is no comma after the STATS_EXIST_EXCEPTION exception, so this cannot be the reason why the procedure cannot be created.

B. b) The STATS_EXIST_EXCEPTION has not been declared as a number. This option is incorrect. The STATS_EXIST_EXCEPTION is not being used as a number, so it does not need to be declared as such. It is being used as an exception.

C. c) The STATS_EXIST_EXCEPTION has not been declared as an exception. This option is correct. The STATS_EXIST_EXCEPTION exception has not been declared in the procedure. Without a declaration, the procedure does not know what to do when the exception is raised. To fix this, the STATS_EXIST_EXCEPTION should be declared as an exception before the BEGIN keyword.

D. d) none of the above This option is incorrect. As explained above, option C is the correct answer.

Therefore, the correct answer is:

The Answer is: C