Final answer:
b) Backward conditioning, where the neutral stimulus follows the unconditioned stimulus, is generally the least effective temporal arrangement in classical conditioning.
Step-by-step explanation:
In classical conditioning, the temporal relationship between the neutral stimulus (NS) and the unconditioned stimulus (US) is crucial for learning. The delay conditioning, trace conditioning, and simultaneous conditioning involve presenting the NS before the US, but with varying intervals connecting them.
Among the options, backward conditioning, where the NS is presented after the US, is typically the least effective. This is because learning is usually more robust when the NS predicts the US, rather than follows it. To illustrate using Pavlov's classic example, presenting the tone after the food (backward conditioning) would not reliably lead to the dogs salivating to the tone alone.