With Regard to Driving and Talking on a Cell Phone

With regard to driving and talking on a cell phone, which of the following conclusions is not suggested by the research?

A) Drivers who are using a hands-free device are not at any increased risk.
B) Drivers slow down when talking on the phone.
C) Drivers have slower reaction times when engaged in driving and phoning.
D) Drives talking on cell phones sometimes stop at green lights.