Answer:
a. reckless
Step-by-step explanation:
You can use context clues from the sentence to figure out what impetuous means. The sentence is saying that while he's an impetuous race car driver/stunt man, he is a cautious businessman with a steady job. So you can infer that how he acts as a race car driver is different than as a businessman, like opposites. Reckless is the opposite of cautious, so it's reckless!
hope this helped :)