The major source of foreign exchange earnings for Nigeria is:

**The reasoning** Nigeria's economy relies heavily on **petroleum exports** for foreign exchange (forex) — money earned from selling goods abroad. When you look at Nigeria's export data, crude oil consistently accounts for **over 80-90% of total export earnings**. This means that for every ₦100 Nigeria earns from foreign countries, roughly ₦85-90 comes from selling crude oil. While agriculture was our backbone before the 1970s oil boom, and while we still export cocoa, cashews, and sesame, these bring in far less forex compared to the billions of dollars from oil exports to countries like India, Europe, and the US. **Why the wrong options tempt you** - **A) Agriculture** — sounds right because Nigeria is naturally agricultural, and it *was* our main earner pre-1970. But currently? It's mostly for local consumption. - **B) Manufacturing** — we actually *import* more manufactured goods than we export, so this is a net forex *consumer*, not earner. - **D) Solid minerals** — Nigeria has gold, tin, coal, but these sectors remain largely underdeveloped and contribute minimally to forex. **Quick takeaway** "Nigeria's foreign exchange = crude oil dominance (80-90%); agriculture feeds us, but oil pays our international bills."