The best option to include in a speech with the purpose to argue about not using cell phones while driving is the first supporting statement:
"Cell phone usage while driving has caused over 300 fatal accidents in 2018 alone."
it is the best choice because it is impersonal, unlike option D, in which the author expresses their own opinion. It is less aggressive than option B, but more direct than option C, in which it is stated that cell phones are helpful and there seems to be nothing wrong with using them when in a car.
Additionally, option A seems more reliable than the rest, because it includes a number of accidents that happened in the past, which implies that the negative effect of driving while using the phone has been studied before.