A country exports crude oil worth $4.2 billion and imports refined petroleum products worth $1.8 billion in a given year. Its balance of trade in the petroleum sector is

Balance of trade = Exports − Imports = $4.2 billion − $1.8 billion = $2.4 billion surplus. A positive result indicates a favourable balance (surplus). Option A incorrectly labels the same figure as a deficit, option B adds instead of subtracting, and option D is entirely incorrect.