In the context of the theoretical differences between Ivan Pavlov's Classical Conditioning theory and B. F. Skinner's Operant Conditioning theory, which of the following statements is most accurate and scientifically valid?

Classical conditioning, propounded by Ivan Pavlov, is a type of learning in which an association is formed between a conditioned stimulus (CS) and an unconditioned stimulus (UCS), and it is controlled by the stimulus, referred to as the 'S-R' paradigm.

In contrast, B. F. Skinner's operant conditioning emphasizes that the organism acts actively in the environment (Response) and its consequences (Stimulus/Reinforcement) determine its behavior, which is referred to as the 'R-S' paradigm.