The correct answer is begin.
A. conduct pretests
B. affix one's signature
The correct answer is C. to begin; to originate; to get going or cause to get going. Also, to admit someone, particularly by introductory rite or form (into society, office, secret, etc.). Finally, to teach the fundamentals of a subject.
Initiate comes from Latin initiare.
Examples of use:
- Our elected member initiated an amendment to the bill.
- The company quickly initiated changes to its product.