The correct answer is guarantee.
A. make crooked
The correct answer is (C) To guarantee; to justify; to give one's word for; vouch for; to give a formal assurance to, or for; to promise, to state as a certainty; to serve as warrant for.
Warrant comes from Old French warantir.
Examples of use:
- The situation warranted immediate action by the manager.
- The manufacturer warranted the product safety of each of its offerings.