As Kathy Approached the Cartersville Airport,she Noticed an Interstate Billboard

As Kathy approached the Cartersville airport,she noticed an interstate billboard with a picture of two mangled cars that appeared to have rammed into each other.At the bottom of the billboard was the name of a brake repair service and its phone number.As she drove home from the Cartersville airport,she saw the same billboard but with a different advertiser's name and phone number.Kathy most likely saw a

A) painted display.
B) junior panel.
C) stock poster.
D) repetitive billboard.
E) mobile billboard.