Leila stared at the driver of the shiny red convertible stopped in the middle of the intersection, incredulous that he would stop traffic just to yell at another driver behind him. What does the use of incredulous connote?

that Leila is envious of the driver for having a convertible
that Leila is angry at the driver for stopping in the intersection
that Leila thinks she might know the driver of the convertible
that Leila is shocked at what the driver of the convertible did