Most bicycle helmets provide good protection for the top and back of the head, but little or no protection for the temple regions on the sides of the head. A study of head injuries resulting from bicycle accidents showed that a large proportion were caused by blows to the temple area. Ttherefore, if bicycle helmets protected this area, the risk of serious head injury in bicycle accidents would be greatly reduced especially since __. Which of the following most logically completes the passage? ['even those bicyclists who regularly wear helmets have a poor understanding of the degree and kind of protection that helmets afford', "among the bicyclists included in the study's sample of head injuries, only a very small proportion had been wearing a helmet at the time of their accident", 'the bone in the temple area is relatively thin and impacts in that area are thus very likely to cause brain injury', 'bicyclists generally land on their arm or shoulder when they fall to the side, which reduces the likelihood of severe impacts on the side of the head']