When of the following matters may account for changes in supply? I - technological advances in an industry II…

Analyze the question: The question asks which of the listed factors can cause a change in supply, meaning a shift of the whole supply curve rather than a movement along it. These are the non-price determinants of supply.

Explain the concept: Supply changes when conditions of production or selling change, even if the price of the good stays the same. The main determinants are:

• Technology
• Cost of factors of production (labour, raw materials, capital)
• Taxes and subsidies
• Number of producers and sources of supply
• Weather and natural factors (especially for agriculture)
• Prices of other goods and producers' expectations

Check each statement:

• I. Technological advances in an industry: Yes. Better technology lowers the cost of production and raises output, so supply increases (the curve shifts right).
• II. Changes in labour costs: Yes. Labour is a factor of production. Higher wages raise costs and reduce supply, while lower wages increase supply.
• III. Changes in source of supply: Yes. A new source of supply (for example new producers, new suppliers of raw materials, or imports) or the loss of an existing one changes the quantity available at each price.
• IV. Changes in levels of taxation: Yes. Higher taxes raise production costs and reduce supply, while lower taxes or subsidies increase supply.

All four statements are valid determinants of supply.

Answer: The correct option is D. I, II, III, IV.

Tip: For supply, think "TCNT-W": Technology, Cost of production, Number of sellers/sources, Taxes and subsidies, and Weather. If a factor is anything other than the good's own price, it shifts the curve. A change in the good's own price only causes a movement along the curve, which is called a change in quantity supplied.