The correct answer is D. all of the above.

A macro processor is a program that expands macros in a source file before compiling it. A macro is a name that is replaced by a string of characters when the macro is expanded. The macro processor must perform the following steps:

1. Recognize macro definitions and macro calls.
2. Save the macro definitions.
3. Expand macros calls and substitute arguments.

When a macro is defined, the macro processor stores the macro definition in a table. When a macro is called, the macro processor looks up the macro definition in the table and expands the macro by replacing the macro name with the string of characters that is stored in the table. The macro processor can also substitute arguments for placeholders in the macro definition.

For example, the following macro definition:

“`

define FOO(x) x * x

“`

can be expanded to the following string:

x * x

The following macro call:

FOO(5)

can be expanded to the following string:

5 * 5

The macro processor must perform all of the steps listed above in order to expand macros correctly.