Tiger moths emit sounds at frequencies similar to those of the ultrasound echolocation calls used by ...

Tiger moths emit sounds at frequencies similar to those of the ultrasound echolocation calls used by bats to locate prey such as moths and other flying insects.
 
  You hypothesize that these calls serve as a warning to bats with which the moths advertise their bad taste. Which among the following studies alone would be the best test of your hypothesis?
  a. compare the response of nave bats (no previous contact with tiger moths) to recorded tiger moth calls with that of experienced bats (previous contact with tiger moths) to the same calls
  b. feed dead tiger moths to bats and observe the bats' reaction
  c. play recorded tiger moth calls to bats and examine whether the bats change flight pattern
  d. place two types of tiger moth models in an arena with bats, with one type of model emitting recorded moth calls, while the other does not