Rail - a bar or series of bars, typically fixed on upright supports, serving as part of a fence or barrier or used to hang things on
road - a wide way leading from one place to another, especially one with a specially prepared surface which vehicles can use.
He discovers how to animate lifeless matter
^^^^^^^^^^^^
The answer is b. because this way you can hear all the characters thoughts and what they are saying. this lets you know how they truly feel versus how they want you to think they feel.
