Explanation:

Option A fits in with the context. The meaning of the words in the given options are:
Ostracism: noun - exclusion, by general consent, from social acceptance, privileges, friendship, etc.
Ex. The conflict between the two leaders ended in the ostracism of Aristides, at a date variously given between 485 and 482
Subsume: verb- to consider or include (an idea, term, proposition, etc.) as part of a more comprehensive one.
Ex. He may finally be ready to subsume his ego and ideology for the sake of his country
Amenable: adjective- ready or willing to answer, act, agree, or yield; open to influence, persuasion, or advice; agreeable; submissive; tractable:
Ex. Rajesh is mostly an amenable servant 
Expatriation: verb (used with object), to withdraw (oneself) from residence in one's native country. 
Ex. What benefit might he derive from Mark's expatriation —that is the question?
Corollary: noun- an immediate consequence or easily drawn conclusion.
Ex. And the corollary is that “those” people are where they are entirely because of their own doing.
Relegation: verb- to send or consign to an inferior position, place, or condition
Ex. With such remains before us it is no longer sufficient to relegate Minos to the regions of sun-myths.
Fusing: to join
Ex. The greater part of the under-jaw is formed by the right and left dentaries, which in all recent birds are fused together in front.
Censure: noun - strong or vehement expression of disapproval
Ex. This brought them under the official censure, and was forbidden.
Option A is hence the correct answer.