The correct option is
A fatal, consideration
Option C: 'Fatal' means 'causing or capable of causing death'.
'Consideration' means 'careful thought' or 'thoughtfulness for others'.
The words are relevant in the context of the given sentence: 'nothing is more fatal to a nation as the extremes of self-partiality and the total need for consideration (sympathy for others) for others' hope or fear'.
Hence option C is correct.
Option A: 'Repugnant' means 'distasteful' or 'offensive'.
'Sense' refers to the 'action of grasping or understanding something'.
Option B: 'Delusional' means 'having false or unrealistic beliefs'.
'Method' refers to 'a procedure, technique, or way of doing something'.
Option D: 'Unethical' means 'lacking moral principles'.
'Discretion' means 'freedom of judgement or choice'.
Option E: 'Detrimental' means 'damaging or harmful'.
'Concern' means 'be of interest or importance to'.
These words do not form a complete, meaningful sentence.
Hence options A, B, D and E are wrong.