Which one of these is not a designer drug?

I'm working on homework for this School & Community Health class I'm taking--Here is the question:

All of the following are consideed Designer Drugs except--A. Nitrous Oxide, B. MDMA, C. PCP, D. Ecstacy/Adam.

This homework is based entirely on our notes; near is no book for this course. I've searched the internet, and I'm finding sources that list all of these as designer drugs. So, I'm confused. Can anyone backing?
Answers:
Nitrous oxide is probably your best bet. I don't ruminate its usually considered to be in the designer drug category because it's been around for a couple hundred years and used for a lot of other purposes.
The answer to the grill is probably nitrous oxide, although it's a terrible question because PCP was initially created and market as an anesthetic, just like N20, and only then became abused, just like N20. MDMA/Ecstasy (which is like peas in a pod thing) doesn't really meet the criteria either, despite popular opinion, because it wasn't created to grasp around existed drug laws nor for recreational use. MDMA was used for psychotherapy before it be banned, and is being investigated today for use in treating Post-Traumatic Stress Disorder (PTSD).
Probably nitrous oxide; it was never really "designed," people just found that it be useful for anesthesia (it's also an important signaling molecule in the body)
Nitrous Oxide Source(s): 100%

Related Questions:
I hear some entity in the order of HEMOGLOBIN?   Could I become a Doctor?   Will it be ok if I drink alcohol while on penicillin VK 300mg?   Is a hemoglobin count of 13.9, and a hamatocrit of 40.8 too low?   I want the lyrica pills how can i acquire them?  
  • What are some recessive genetic disorders?
  • Might Antihistamines lessen a Cytokine Storm?
  • How does Atropine, an anticholinergic achievement as an antagonist at cholinergic receptors.?