Concept:The Railway Corporation in West African countries is a public enterprise, so its main funding comes from government support rather than private business earnings.
Explanation:The Railway Corporation often does not generate enough revenue from passenger or freight services to cover its operating costs.
A surplus refers to excess income over expenditure, which is not a reliable external source of finance for a public corporation.
Sale of shares is usually used by private joint-stock companies, not by government-owned railway corporations.
Trade credit is short-term credit from suppliers of goods and services, which is not the primary source of finance for capital-intensive railways.
Government subvention is a recurring financial grant or aid given by the government to public enterprises to support their operations and maintenance.
In West African countries, the government provides this subvention as the major source of finance to keep the Railway Corporation running.
Answer:D. government subvention