Being able to drive a car while you carry on a conversation with a friend in the passenger seat is explained by:

a)the ability to automatize the conversation and dedicate the majority of your attention to driving.

b)the cocktail party phenomenon, which allows you to attend to the important parts of both tasks.

c)the ability to automatize driving and dedicate the majority of your attention to the conversation.

d)this is not actually possible, because your attention is divided between the tasks.