Option D is the correct answer because “paradox” means a seemingly absurd or contradictory statement or proposition which when investigated may prove to be well founded or true, here in this case the high save and low growth rates are completely contradictory, and hence it is correct.
Option A is incorrect because “irony” means the expression of one's meaning by using language that normally signifies the opposite, which is not the case here because the statement true a to explain the contrary saving and growth effects.
Option B is incorrect because “similarity” means being similar or the same, to match, which is incorrect here because the statement is about the contrary saving and growth rate figures.
Option C is incorrect because “difference” means to differ or not be the exact same, which has a different meaning from “contrary” or “paradox”, hence it is incorrect.