To solve this question, the user needs to know the different ways to pass parameters to a subprogram in programming languages.

The options in the question are using the "CALL" statement to pass a copy of the identifier to a subprogram. The CALL statement is used to transfer control to a subprogram (procedure or function) and pass arguments, if any.

Now, let's go through each option and explain why it is right or wrong:

A. (a) CALL . . . BY CONTENT literal: This option is incorrect because it passes a literal value to the subprogram, not an identifier. The "BY CONTENT" phrase specifies that the value is passed by value, which means a copy of the value is passed to the subprogram.

B. (b) CALL . . . BY CONTENT identifier: This option is correct because it passes a copy of the identifier (variable name) to the subprogram. The "BY CONTENT" phrase specifies that the value of the identifier is passed by value, which means a copy of the value is passed to the subprogram.

C. (c) CALL . . . BY CONTENT ADDRESS OF identifier: This option is incorrect because it passes the address of the identifier to the subprogram, not a copy of the value. The "BY CONTENT ADDRESS OF" phrase specifies that the address of the identifier is passed by value, which means a copy of the address is passed to the subprogram.

D. (d) CALL . . . BY CONTENT ADDRESS OF identifier: This option is incorrect because it is the same as option C, which passes the address of the identifier to the subprogram.

Therefore, the correct answer is:

The Answer is: B. (b) CALL . . . BY CONTENT identifier