Final answer:
The controlled substance among the medications listed is Hydrocodone with APAP due to its potential for abuse and dependence, and it is classified under Schedule II controlled substances in the United States.
Step-by-step explanation:
The controlled substance among the listed medications is D. Hydrocodone with APAP. These medications belong to different classes of drugs. Trazodone HCI (Desyrel) is an antidepressant, Atenolol (Tenormin) is a beta-blocker used for cardiovascular issues, and Furosemide (Lasix) is a diuretic for reducing swelling and fluid retention. However, Hydrocodone is an opioid pain medication that is regulated as a controlled substance due to its potential for abuse and dependence.
Specifically, Hydrocodone with APAP combines hydrocodone, which is an opioid analgesic, with acetaminophen, a non-opioid pain reliever. Due to the presence of hydrocodone, it is classified under Schedule II controlled substances in the United States by the Drug Enforcement Administration (DEA), indicating a high potential for abuse and severe psychological or physical dependence.