Concept:The correct word is the one that means preparing land for planting crops.
Explanation:The sentence talks about working on the land to get a good harvest.
"Water" means to supply moisture, not prepare the soil.
"Dig" means to break up the earth, but not the full process of preparing land.
"Cultivate" means to prepare and use land for growing crops.
"Clear" means to remove obstacles, which is only a part of preparation.
Therefore, the best word is "cultivate".
Answer:C. cultivate