I have a subscription as I am over 50. I just checked and Eden123 is correct that there is now a section on the global shortage, it still lists source B (D)'s e-mail and says that he supplied "until the global shortage..." and then says "payment is/was by Bitcoin or Monero". So it looks like they are still listing him but are unsure if he is still currently a reliable source.
I don't know how to upload screenshots, but here is what the new section says:
"Since mid-2021 there has been a slow, building global shortage of veterinary Nembutal. This has occurred both because of the pandemic but also because of a reported catastrophic incident at one of the two global manufacturing sites of the drug (see
https://www.sheltervet.org/assets/PDFs/Euthanasia solution shortage in shelters_final.pdf ). While the shortage has been many months in the making, it was not until the second quarter of 2022 that the impact of the lack of supply started to be felt. While Nembutal can still be purchased over-the-counter in some Sth American countries, its availability on the Internet has been significantly impacted. Those who trade (illegally) in Nembutal cannot get supply."