He had been sitting in the car for a while waiting for us and listening to the radio . When he went to start his car the battery was dead . So we decided to take my car over there instead . I always hate having to park the car somewhere because then I have to worry is someone going to notice it or is it going to get towed or whatever .

Question: What caused the car battery to be dead ?
Answer: The car battery was old and had to be replaced .None of the above choices .The warranty expired on the car .Using auxiliary power while playing the radio in the car killed the battery .