Correct option is C
Option (c) is the correct antonym of the given word.
Timid means lacking in confidence or showing a reluctance to take risks.
Synonyms: shy, fearful, hesitant, and reserved.
Antonyms: bold, courageous, confident, and fearless.
Meanings of all options-
Diffident: Lacking confidence in oneself.
Shy: Being reserved or hesitant in social situations.
Bold: Displaying a fearless and daring attitude.
Fearful: Experiencing fear or anxiety.