The word 'timid' fits the blank, implying a lack of boldness or confidence. This fits the context of someone who is shy or reluctant.
- Option (a) 'Bold' would imply confidence, which is the opposite of what the sentence is suggesting.
- Option (c) 'Forthcoming' suggests someone who is open or willing to speak, but it doesn't fit the context of the sentence.
- Option (d) 'Brazen' suggests someone who is shamelessly bold, which is contrary to the meaning of the sentence.
Thus, (b) Timid is the most fitting word.