When the patent is running out of a drug that made the company a lot of moneyWhen the patent is running out of a drug that made the company a lot of moneya. they find various ways to extend its patent, including making minor changes in its contentsb. they will try to get its users to switch to its new, patent$-$protected and therefore expensive new versionc. they will give it away for free as "samples" to try to get doctors hooked on prescribing it and patients used to taking itd. all of the above