Select the appropriate antonym for the underlined word.

There can't be anything positive about plastics with pathogens floating around.

depreciative

The correct answer is option 3. depreciative.

In the given sentence, the speaker is expressing a negative sentiment about plastics, suggesting that there is nothing positive about them, particularly in the context of pathogens floating around. Therefore, the speaker's tone is one of depreciation or devaluation towards plastics.

"Depreciative" means expressing disapproval or negative sentiment towards something. It aligns with the negative tone conveyed in the sentence. Therefore, "depreciative" is an appropriate antonym for the underlined word, indicating an opposite sentiment to approval or positivity.