The correct answer is Abundance. The word 'dearth' means a scarcity or lack of something, a severe shortage. Therefore, its antonym, or opposite, would describe a situation where there is a plentiful supply or a great amount of something. 'Abundance' precisely conveys this meaning, signifying a very large quantity of something, making it the direct opposite of a dearth.
Option A, Scarcity, is incorrect because it is a synonym of dearth, meaning a shortage or lack, not its antonym.
Option C, Poverty, is incorrect. While poverty often implies a lack of resources, it specifically refers to the state of being extremely poor, which is a broader concept than just a general shortage of something. It is not a direct antonym for 'dearth' in all contexts.
Option D, Shortage, is incorrect because it is also a synonym of dearth. Both words indicate an insufficient amount of something, making them similar in meaning rather than opposite.