Final answer:
The red and white speckled mushroom known for its use in religious ceremonies is the Amanita muscaria.
Step-by-step explanation:
The red and white speckled mushroom that has been associated with an early Christian cult as well as with other religions all over the world is C) amanita muscaria. The Amanita muscaria, also known as the fly agaric, is recognized for its distinctive bright red cap with white patches. This mushroom contains a hallucinogenic compound called muscimol, which was used in ritualistic ceremonies in prehistoric Europe. Although it can be poisonous, its psychoactive properties have been significant in various spiritual and religious contexts throughout history. It is important to note that this mushroom should not be handled or ingested without proper knowledge, as it can be toxic.