Correct option is A
The correct antonym of the given word is (a)
faulty.
INFALLIBLE: Incapable of making mistakes or being wrong; always right or trustworthy. (अचूक, जिसमें गलती न हो)
Example: His methods are considered infallible by his team.
FAULTY: Having faults or defects; imperfect. (दोषपूर्ण)
Example: The faulty wiring caused a short circuit.
Synonyms of Infallible: flawless, perfect, foolproof, certain.
Antonyms of Infallible: faulty, fallible, imperfect, questionable.
Meanings of other options:
· (b)
Unfailing – always effective (निश्चित रूप से होने वाला)
· (c)
Dependable – trustworthy (विश्वसनीय)
· (d)
Reliable – trustworthy and consistent (भरोसेमंद)