............................ Many online shops have user-friendly websites because
they are-
a) out of site b) easy to operate c) out of reach d) difficult to
The question here is what "they" refers to
1- If it refers to "user – friendly websites then the correct answer is b)
2- If it refers to "Online shops" then the correct answer is c)
This sentence focuses on "Online shops" which try to increase their sales by all means and create themselves websites because not many customers can reach these shops (out of reach ) either because they are in other countries or they don't have real shops . Their shops are virtual and are only available on the web .
So my conclusion is that "out of reach" is the most correct as the shade of meaning implies .
My regards and respect to all