The correct option is A Complaints
Words that are similar to each other in meaning are also known as synonyms of each other. The word ‘Grievances’ means complaints pertaining to problems or things that are otherwise wrong and unfair. While ‘Problems’, 'Obstacles' and ‘Hardships’ are tangentially related to the word, ‘Complaints’ is the closest in meaning to ‘Grievances’ – leaving us with the correct answer, Option A).