**Core Concept**
Schedule-3 of the Medical Council of India (MCI) Code of Ethics Regulations 2002 is a list of prohibited drugs that can be used only in emergency situations. These drugs have a high potential for abuse and addiction.

**Why the Correct Answer is Right**
Schedule-3 includes substances such as morphine, codeine, and pethidine, which are opioid analgesics with a high potential for dependence and abuse. These medications are strictly regulated and can only be used in life-threatening situations or under specific circumstances. The MCI schedule-3 includes these drugs to ensure their safe use and prevent overuse or misuse.

**Why Each Wrong Option is Incorrect**
**Option A:** Schedule-3 does not include antibiotics like ampicillin or ciprofloxacin, which are commonly used to treat bacterial infections.
**Option B:** Schedule-3 is not related to the list of essential medicines or the WHO Model List of Essential Medicines.
**Option C:** Schedule-3 does not include vaccines or immunoglobulins, which are used to prevent or treat infectious diseases.

**Clinical Pearl / High-Yield Fact**
Remember that Schedule-3 substances have a high potential for abuse and addiction, and their use should be strictly regulated and monitored.

**Correct Answer:** A. Morphine, codeine, and pethidine are the examples of Schedule-3 substances.