Which of the following factors is not a condition for a change in the supply of a commodity

Analyze the question: The question asks which factor is not a condition (determinant) of supply. In economics, we separate:

• Change in quantity supplied: caused only by a change in the commodity's own price (a movement along the supply curve).
• Change in supply: caused by other factors, which shift the whole supply curve.

Explain the concept: The conditions of supply (the factors that shift the supply curve) include:

• Technology
• Cost of production (wages, raw materials, rent)
• Government policies (taxes, subsidies)
• Number of firms in the industry
• Weather and natural conditions (especially for agricultural goods)
• Prices of related goods
• Expectations of future prices

Solution, option by option:

• A. Improved technology: lowers production costs and increases output at every price, so the supply curve shifts right. This is a condition of supply.
• B. Cost of production: higher costs reduce supply, and lower costs increase it. This is a condition of supply.
• C. The price of the commodity: a change in the commodity's own price only moves us along the same supply curve, giving a change in quantity supplied, not a change in supply. This is not a condition of supply.
• D. Government tax policies: taxes raise costs and subsidies lower them, so the curve shifts. This is a condition of supply.

Exam tip: Remember the phrase "own price = move along, anything else = shift." WAEC often tests the difference between change in supply (shift) and change in quantity supplied (movement along the curve). The same idea applies to demand.