two robots.txt on a domain

i have a domain with two scripts

1 script is on root forlder with its own robots.txt

2 script is on a folder /x

im testing my robots.txt on google webmaster but what should i do?


a : Add second script robots rules into root robots.txt

like

User-agent: *

disallow: /x/images


b : or i should use its own robots.txt from "X" direcory?

User-agent: *

disallow: /images

Go with the option 'b'

I prefer option A.
But anyway I do not believe Google pays attention to robots.txt for past 2-3 years.