"Agitate" means to disturb, excite, or make anxious. The opposite or antonym would be "Soothe," which means to calm or pacify. Therefore, option (D) Soothe is the most suitable antonym in this context.

"Insatiable" refers to an inability to be satisfied or appeased. The opposite or antonym would be "Fulfilled," indicating a state of being satisfied or content. Therefore, option (B) Fulfilled is the most suitable antonym in this context.

"Alleviate" means to make something more bearable or less severe, while "Aggravate" means to make something worse or more intense. Therefore, option (C) Aggravate is the most suitable antonym in this context.

"Absurd" means wildly unreasonable or illogical, so the opposite or antonym would be "Reasonable," which denotes something logical and sensible. Therefore, option (D) Reasonable is the most suitable antonym in this context.

"Difference" implies a degree of dissimilarity or distinction, and "Similarity" represents the opposite, indicating things that are alike or have common features. Therefore, option (A) Similarity is the most suitable antonym in this context.

"Praise" involves expressing approval or admiration, while "Condemn" involves expressing strong disapproval or criticism. Therefore, option (B) Condemn is the most suitable antonym in this context.

"Detrimental" means causing harm or damage, so its antonym would be "Harmless," which indicates something that does not cause harm or injury. Therefore, option (B) Harmless is the most suitable antonym in this context.