The quantity supplied is the:
a. incremental cost of producing one more unit of output, holding all other things constant.
b. change in the sellers' output multiplied by the change in price.
c. amount of a good that firms are willing and able to sell at a particular price during a given period of time.
d. amount of inputs that a firm earns profit on.

c. amount of a good that firms are willing and able to sell at a particular price during a given period of time.

Explanation:

Quantity of any goods that a business is willing to sell at a particular price during a given time period is called Quantity supplied. For Example when the price of an apple $1 the quantity supplied is 200 apples a week. if the price falls to $0.85 per apple the quantity supplies will fall to 150 apples a week. So, Quantity supplied at $1 is 200 apples and at $0.85 is 150 apples per week.

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b. a single paragraph.

a paragraph is a series of sentences that are organized and make sense, and are all related to a single topic . almost every piece of writing you do that is longer than a few sentences should be organized into paragraphs. this is because paragraphs show a reader where the subdivisions of an essay begin and end, and thus the reader see the organization of the essay into subjects in order to be able to understand its main points.