Final answer:
The prices at the producer level are higher compared to B)those of a year ago and are going down, despite the adverse effects of floods and drought on crops, which have led to a rise in corn and soybean prices.
Step-by-step explanation:
The correct answer is B. Than those a year ago and are going down, even though floods in the Midwest and drought in the South are hurting crops and therefore raising.
The sentence is discussing the prices at the producer level, which are higher compared to those of a year ago. The prices are going down, despite the adverse effects of floods and drought on the crops, which have led to a rise in corn and soybean prices.
Therefore, option B uses the correct verb tense and the appropriate verb form ('raising') to accurately convey the cause-effect relationship between the floods/drought and the price increase.