Which of the following is a drug classified under Penalty Group 2?

MDMA, commonly known as ecstasy, is classified under Penalty Group 2. This classification encompasses substances that have a high potential for abuse and that are considered dangerous in terms of their effects on the body and mind. Penalty Group 2 includes a range of hallucinogenic and stimulant drugs, and MDMA is specifically recognized for its psychoactive properties which lead to alterations in mood and perception.

In contrast, LSD is also a hallucinogenic drug but falls under Penalty Group 1 due to its severe potential for abuse and lack of accepted medical use. Oxycodone, a prescription opioid, is classified under Penalty Group 1 as well due to its potential for addiction and misuse. Heroin, an opioid derivative, is likewise under Penalty Group 1 for similar reasons. Therefore, MDMA stands out as the correct choice because it is specifically identified within the criteria of Penalty Group 2.