Answer: A
While being sagacious is considered to be a positive trait in a person, cunning is the negative aspect of the same trait. Similarly, being confident is considered to be a good thing, while being arrogant is a negative extension of confidence.

Answer: D
Just as ‘allay’ meaning to soothe or pacify is the opposite of ‘worsen’, ‘malign’ which means to defame is the opposite of praise.

Answer: B
‘Exult’ which means to express extreme joy is a synonym of ‘rejoice’. Similarly, ‘Complicate’ which means to make intricate or involve is a synonym of ‘Perplex’.