Economics · Foreign Exchange Management

In the context of foreign exchange management, consider the following situations: I. A sustained depreciation of the domestic currency due to speculative capital outflows. II. A sharp fall in foreign portfolio investment inflows. III. A persistent current account deficit financed through volatile capital flows. IV. An abrupt appreciation of the domestic currency driven by excess capital inflows. In which of the above situations is the central bank most likely to intervene by selling foreign exchange reserves?