All of the following are types of Vitamin B12 except?

Vitamin B12, also known as cobalamin, has several forms, including Hydroxocobalamin, Methylcobalamin, and Adenosylcobalamin. Hydroxocobalamin is a natural form of Vitamin B12 often used in injections and is known for its ability to be converted into active forms in the body. Methylcobalamin is the form of B12 that is readily utilized in the nervous system and is crucial for the synthesis of neurotransmitters. Adenosylcobalamin, also known as dibencozide, is another active form that plays a vital role in energy metabolism.

In contrast, Phytomenamin is not a type of Vitamin B12; rather, it is another name for Vitamin K1 (phylloquinone), which is involved in blood clotting and bone health. This distinction highlights that while the other options are active forms of Vitamin B12 with roles in various biological processes, Phytomenamin belongs to a different vitamin category altogether.