Final answer:
Separate compilation is preferable because it allows for modular programming, reduces build times, and enables code reuse.
Step-by-step explanation:
Separate compilation is preferable for several reasons. Firstly, it allows for modular programming, where different parts of a program can be developed and compiled separately. This makes the code easier to manage and maintain. Secondly, separate compilation reduces build times, as only the modified part of the code needs to be recompiled, instead of the entire program. Finally, it enables code reuse, as compiled object files can be reused in different programs or projects.