Insects, instincts, behavior, brain size.
My answer: (E) "Only organisms with brains of insect size or smaller engage in purely instinctual behavior."
Credited answer: (B) "Insect behavior is exclusively instinctual."
The credited answer seems much more restrictive. It's an absolute, which I read no grounds for in the argument.
The argument never cites a binary for behaviors (i.e. instinctual/flexible), so why is it necessary that insect brain size < required size for flexible behavior ----> insect behavior = pure instinct?
I felt the more qualified statement in (E) was appropriate. Please advise.