Why is texting while driving more dangerous than having a vocal conversation with someone while driving?

a. Texting while driving has more auditory cognitive overlap than having a vocal conversation while driving.

b. Cognitive interference occurs while texting and driving but not when conversing and driving.

c. Cognitive interference only occurs when different sensory stimuli are used at the same time.

d. There is greater cognitive overlap and interference while texting and driving than while driving and having vocal conversations.