Theory predicts that communication between mutualistic species should be favored if such ...

Theory predicts that communication between mutualistic species should be favored if such communication results in an increase of individual fitness in both species.
 
  Can the experiment displayed below determine whether communication results in a fitness advantage in Iri-domyrmex ants and imperial blue butterflies?
 
  a. Yes, the experiment tests whether caterpillars communicate with ants; communication would not evolve in the absence of a fitness advantage.
  b. Yes, ants that respond to butterfly pupa stridulations have a higher fitness.
  c. No, gain or loss of fitness is not tested in this experiment.
  d. No, only the ants' fitness is tested.