Which Statement Best Characterizes the Textbook Authors' Views with Respect

Which statement best characterizes the textbook authors' views with respect to the legacy of behaviourism?

A) The principles of behaviourism have been widely and successfully applied to human problems.
B) The principles of behaviourism ultimately fail because they are not based on carefully controlled laboratory experiments.
C) Behaviourism has been relatively unsuccessful because it places too little emphasis on determining the antecedents and consequences of behaviour.
D) Behaviourism has been successful because,unlike other perspectives,it has based most of its conclusions on research with human participants.