Final answer:
The concept that best matches the relationship between the available supply of a commodity or service and its price is the supply/demand curve, which illustrates how quantity supplied is affected by changes in price.
Step-by-step explanation:
The relationship between the available supply of a commodity or service and its price is best represented by option 2) supply/demand curve. This concept illustrates how the price of a commodity or service influences the quantity supplied in the market. According to the Law of Supply, there is a direct relationship between price and the quantity of a good that producers are willing to offer for sale. When prices rise, the quantity supplied tends to increase, and when prices fall, the quantity supplied usually decreases.
Another aspect of this relationship is represented by a supply curve, which is a graphical representation of the correlation between the price of a commodity and the quantity supplied, holding all other factors constant (ceteris paribus). This curve typically slopes upwards from left to right, reflecting the inclination of businesses to increase output as prices rise. Shifts in the supply curve can occur due to various factors, such as changes in production costs, technology, number of sellers, and government policies.