Question ID:PT84 S2 Q10 Passage:Various studies have concluded that song overlapping, the phenomenon where one bird begins a song while another of its species is singing, is a signal of aggression. These studies are based solely on receiver-response tests, which seek to derive conclusions about the intent of a signal based on how others respond to it. However, any response‚ even no response‚ can be interpreted as a reaction to perceived aggression. Therefore, _______. Stem:Which one of the following most logically completes the argument? Correct Answer Choice:EChoice A:birds do not respond in a predictable manner to signals of aggression Choice B:receiver-response tests can provide no insight into bird behavior Choice C:song overlapping is likely not a signal of aggression Choice D:song  overlapping has no communicative function Choice E:the conclusion of these studies is unconvincing