Botulinum Toxin Belongs to a Group of Toxins Called A-B

Multiple Choice

Botulinum toxin belongs to a group of toxins called A-B toxins.What does the term "A-B" refer to?

A) Their antigen-binding properties.
B) Their antibody-binding toxins.
C) Their enzymatically active subunit and cell binding subunit.
D) Their action on the brain.
E) Their activation of B-cells.