Words that are similar to each other in meaning are also known as synonyms of each other. The word ‘Appraisal’ means to assess someone formally and thoroughly, and then make a judgement or estimation of their performance. Both ‘Enlightenment’ and ‘Application’ are irrelevant in terms of meaning to the word, ruling out Options B) and D); and while ‘Application’ is only tangentially related to the word. Thus, ‘Estimation’ is the closest in meaning to ‘Appraisal’ – leaving us with the correct answer, Option A).