Step 1: Analyze the director’s decision.
Casting an unknown actor is generally seen as a bold or uncertain move. Words like "risky," "audacious," and "unconventional" suggest this. "Prudent" implies caution, which does not fit.
Step 2: Analyze the actor’s performance.
Since the decision was viewed as "risky" or "audacious," the performance likely matched this boldness, implied here by "audacious" also fitting well to describe the decision itself.
Step 3: Choose the two best answers.
The best pair to fill the blanks to reflect a daring decision is "risky" and "audacious."