The market supply curve slopes upward from left to right indicating that?

Step 1: Analyze the question The question asks what an upward-sloping market supply curve (rising from left to right) tells us.

Step 2: The concept The law of supply says that, other things being equal, the higher the price of a good, the greater the quantity producers are willing to supply. The lower the price, the smaller the quantity supplied. Price and quantity supplied move in the same direction, so the curve slopes upward.

Step 3: Check each option

• A. Producers pay high taxes. Taxes shift the supply curve. They do not explain its upward slope.
• B. Two commodities can be supplied at the same time. This has nothing to do with the slope of a supply curve for a single commodity.
• C. At a lower price, less is supplied. Correct. Moving down the curve to a lower price, the quantity supplied falls. This is the law of supply.
• D. At a lower price, more is supplied and demanded. Wrong. More supplied at a lower price contradicts the law of supply. More demanded at a lower price is the law of demand, which is a different curve.

Step 4: Answer

Exam tip: Remember "Supply follows price": the quantity supplied goes up when the price goes up, and down when the price goes down. Demand does the opposite, and its curve slopes downward. If an option mixes supply and demand behaviour, as D does, it is almost always a trap.