Correct option is A
Option (a) is the correct antonym of the given word.
Steadfast: Firmly committed or unwavering in one's beliefs, actions, or loyalty; resolute and unchanging.
Synonyms: Resolute, unwavering, loyal, determined.
Antonyms: Fickle, wavering, disloyal, inconsistent, unreliable, dishonest.
Meanings of all options-
Dishonest - Not truthful or lacking integrity; inclined to deceive or cheat.
Unwavering - Firm and steadfast in beliefs, actions, or loyalty; not changing or faltering.
Immobile - Lacking the ability to move; stationary or fixed in one place.
Dependable - Trustworthy and reliable; able to be counted on to fulfill obligations or duties.