Select the option that expresses the opposite meaning of the highlighted word.
The explosive used is of my own formulation, and I can vouch for its efficiency.

Correct option is C

The correct antonym of vouch is invalidate.
Given word: Vouch - To affirm or confirm the truth or authenticity of something.
Hindi Meaning: समर्थन करना, पुष्टि करना
Synonyms: affirm, certify, endorse, verify.
Antonyms: invalidate, refute, disprove, reject.
Explanation: Vouch means to confirm or guarantee, while invalidate means to nullify or make something unsound or incorrect.
Meanings of other options:
· Maintain: To keep something in good condition.
· Certify: To officially recognize or confirm something as true.
· Witness: To see an event happen.