How does one become a good defensive driver?

Answer: C — Practicing good observation habits and keeping updated on rules

Becoming a good defensive driver involves more than just simply relying on one's driving skills. While driving skills are important, it is also crucial to practice good observation habits and stay updated on rules and regulations. Ignoring the actions of other drivers can be dangerous and not following the speed limit at all times can also be unsafe. Therefore, C is the most comprehensive and accurate answer.