Someone who is willing to take risks or to do something shocking

The best substitute for "Someone who is willing to take risks or to do something shocking"' is Audacious. Audacious means bold to the point of shock or risk-taking. This fits perfectly for someone who does shocking or daring things.

The other options are less accurate because "Bodacious" (option A) means remarkable/attractive (slang), not necessarily risky/shocking, "RIsk-taker" (Option B) describes risk taking behaviour but isn’t a single-word synonym for shocking boldness, and "Bold" (option D) means confident an fearless, this too lacks the shocking/rule-breaking nuance of "audacious." Both B and D lack the complete idea required in the question. 

Hence, Option C is the correct choice.