Explanation:

Option A has the word ‘Keep’ for the second blank but usage of 'keep' for the blank does not make any sense in the context. ‘Fortress’ is also unsuitable as it means a building to defend against an attack.
‘Dungeon’ is a dark prison so it is also inappropriate in the context. Option D also gets eliminated immediately.
Similarly, either of the words 'acquaintance' which refers to 'knowledge or experience of something' or 'prejudice' which refers to 'preconceived opinion that is not based on reason or actual experience' doesn't add any meaning to the context either and thus option B and C get eliminated too.
Here, the presence of word ‘confusion’ in the sentence makes us clear that we need a contrary word in the first blank to comprehend to the context of the sentence. As a result, only "awe" from option E, which can be portrayed as the perfect contrarian to confusion, will be the correct answer. Other options when matched with ‘confusion’ on the contrarian basis, will not make any sense here. Plus, usage of the word ‘Citadel’ which means stronghold or bastion, goes well with the context, if used for the second blank.
Option E is hence the correct answer.