obviously the best answer choice here is E, and I realize this is an early question so no need to be super detailed and nit picky but technically we can not necessarily infer E from the stimulus, right?
It might be that there are other places riodinid caterpillars in South America can go (other than a South American ant colony's territory) that would possibly full proof them from a successful attack by wasps (the stimulus says nothing to preclude this possibility) so there technically is no way of saying, just based on the stimulus, definitively that "riodinid caterpillars in South America that live among ants are less likely to be attacked successfully by wasps than those that do not live among ants" because we simply do not know about all the other non-ant colony places that riodinid caterpillars live and how effective they are in defending them (they may even be more effective in defending them or just as effective and in either case we cannot infer that riodinid caterpillars would be "less likely" to be attacked successfully by wasps living among ants than not living among ants). Do you agree?
thanks!