If you don't fasten your helmet properly, what is the risk you face?

Answer: B — It flying off in an accident

When a helmet is not properly fastened, the most significant risk is that it may fly off in an accident. Helmets are designed to provide essential protection in the event of a crash, and if they're not securely fastened, they cannot function properly. During a collision, the sudden force can easily dislodge a loose helmet, leaving your head vulnerable to injury. While a loose helmet can indeed cause distractions or potentially hinder your vision, these factors are secondary to the critical role that a secure fit plays in ensuring the helmet remains on your head during an accident. The purpose of a helmet is to protect the rider's head, and if it is at risk of coming off, it jeopardizes that protection. Therefore, ensuring that helmets are worn correctly and fastened securely is vital for rider safety.