Which of the following are the principles tasks of the linker ?
I. Resolve external references among separately compiled program units.
II. Translate assembly language to machine code.
III. Relocate code and data relative to the beginning of the program.
IV. Enforce access-control restrictions on system libraries.
- $I$ and $II$
- $I$ and $III$
- $II$ and $III$
- $I$ and $IV$
