Which of the following is a determinant of elasticity of supply?

Step 1: Analyze the question The question asks for a determinant of the elasticity of supply (price elasticity of supply, PES), which measures how responsive the quantity supplied is to a change in price. It does not ask about demand.

Step 2: Concept Factors that determine elasticity of supply include:

• Time period: supply is more elastic in the long run.
• Durability/perishability of the product: durable goods can be stored, so supply can respond to price changes. Perishable goods have inelastic supply.
• Availability of inputs/raw materials
• Mobility of factors of production
• Spare (unused) capacity
• Nature of the production process / gestation period (e.g., agricultural products vs. manufactured goods)
• Ease of storage

Step 3: Eliminate the options

• A. Consumer's income: a determinant of demand, not supply.
• B. Degree of necessities: whether a good is a necessity or luxury affects price elasticity of demand.
• C. Durability of the product: affects how easily the product can be stored and supply adjusted, so it is a determinant of elasticity of supply. ✔
• D. Number of uses of the commodity: affects elasticity of demand (more uses mean more elastic demand).
• E. Proportion of income spent on the product: also a determinant of elasticity of demand.

Step 4: Answer Only option C relates to the supply side. Durable goods can be stored and released onto the market when prices rise, so their supply is more elastic. Perishable goods must be sold quickly, so their supply is inelastic.

Tip: In elasticity questions, first decide whether the question is about demand or supply. Income, necessity, number of uses, and proportion of income are all demand factors. Time, storage/durability, inputs, and spare capacity are supply factors.