Coherence in stress testing implies that the scenario is logically sound, mathematically possible, and economically plausible.

Option A is the greatest cause for concern because it violates mathematical and economic constraints. The USD, EUR, and JPY represent the vast majority of the weight in any standard "basket of world currencies." It is mathematically impossible for the major components that make up a basket to all depreciate simultaneously against that basket, as currency values are relative.

Option B is highly coherent; during periods of stress, correlations tend to move toward 1. Option C reflects a standard "flight to quality," where investors sell risky assets (driving BBB yields up) and buy safe-haven assets (driving short-term AAA sovereign yields down). This is completely coherent. Option D reflects standard macroeconomic monetary policy, where central banks raise rates to cool down inflation. This is also completely coherent.