Explanation:

BoP is composed of current account as well as capital account. Current account deficit is shown as CAD which comprises of trade surplus/deficit; invisibles surplus/deficit, remittances outflow/inflow etc. Capital account consists of external commercial borrowings, loans taken by government, long-term investments abroad, FDI, FII etc. So, even if CAD is in surplus, it is possible that foreign debt and capital outflows (capital account) are more than CAD. This makes the BoP negative, and there is a net outgo of foreign exchange reserves in this case. So, option (b) is not always correct. Same is true for option (c). Even if trade is in surplus, total CAD and BoP may be negative. So, option (c) is also incorrect. Similarly even if capital account is in surplus, it is possible that CAD is highly in deficit. Thus, there may be a net outgo of foreign exchange. So, option (d) is also incorrect.