What does the supply of a good refer to?

The supply of a good is defined as the quantity of that good that producers are willing and able to offer for sale at various prices during a certain time period. This definition emphasizes the relationship between the price of the good and the quantity supplied, highlighting that supply is influenced by price levels. When prices rise, the quantity supplied typically increases as producers are incentivized to produce more products to maximize profits.

The emphasis on "at a particular price per unit of time" is crucial, as it indicates that supply is not static; it varies with market conditions and time frames. This dynamic is a fundamental concept in economics, affecting market equilibrium and pricing strategies.

The other options focus more on aspects of stock or production without capturing the essential relationship between price and quantity. Therefore, understanding that supply is directly linked to both pricing and the time dimension is key to grasping market behavior and producer decisions.