Bunuel
In the panopticon, a unique type of prison designed by English philosopher Jeremy Bentham in 1785, cells were arranged around a central observatory,
where the occupier could not be seen by the incarcerated prisoners.
A. where the occupier could not be seen by the incarcerated prisoners
B. whose occupier could not be seen by the incarcerated
C. the occupier of which was not able to be seen by the incarcerated
D. having no ability for the occupier to see the prisoners
E. with no possibility of the occupier being seen by the prisoners
Though this question does not 'sound' official, since it tests vocabulary in parts, let me give it a shot:
A. where the occupier could not be seen by the
incarcerated prisoners - redundancy; both words mean the same.
B. whose occupier could not be seen by the incarcerated -
well, this sounds ok! 
Also, 'whose' is correctly referring to the central observatory.
C. the occupier
of which was not able to be seen by the incarcerated - verbose; can be replace by just one word - 'could' ; also, whose occupier are we talking about in this option?
D. having
no ability for the occupier to see the prisoners - Is it? This conveys the opposite meaning.
E. with no possibility of the occupier
being seen by the prisoners - They are all dead ! And 'being seen' anyway is not making sense here.