Concept:The word "enough" means as much or as many as required to serve a specific purpose.
Explanation:In the given sentence, "enough money" refers to the exact amount needed to buy a house.
Option A, "plenty," suggests more than the required amount, so it is not the closest match.
Option B, "much," merely indicates a large quantity and does not convey the idea of adequacy.
Option C, "sufficient," means exactly as much as is needed, which directly matches the meaning of "enough."
Option D, "full," means completely filled or maximum, which does not fit the context of money required.
Therefore, the nearest in meaning to "enough" is "sufficient."
Answer:C. sufficient