According to Recent Research, Which of the Following Is True

According to recent research, which of the following is true with respect to the dangers of cell phone use while driving?

A) Hands-free devices are much more dangerous than hand-held devices.
B) Hands-free devices are much safer than hand-held devices.
C) Hands-free devices appear to be just as hazardous as hand-held devices.
D) none of these.