How does the author's purpose in paragraphs 15-16 in the text IN DEFENCE OF CASH

i think the answer might compound

the answer is b. i read this story before.

a constant variable, normally called a controlled variable, is the term for a variable that remains constant throughout an experiment, though other variables may change. an example is the water pressure for a faucet when measuring the amount of water released when the faucet is opened to various increments.