Radical behaviorism pioneered by BF Skinner expanded the scope of behaviorism to include private events eg thoughts feelings sensations as behavior Unlike methodological behaviorism which explicitly excluded private events from scientific analysis due to their unobservability radical behaviorism considers them legitimate behaviors However because private events are internal and only accessible to the individual they cannot be directly observed or reliably measured by others For this reason while ABA practitioners acknowledge their existence and influence they are typically not included as direct targets in behavior change plans Instead overt observable and measurable behaviors that are functionally related to or indicative of private events are targeted Option A is incorrect because private events are considered behaviors under radical behaviorism Option C is incorrect because methodological behaviorism did not acknowledge private events as behavior this was a key distinction introduced by radical behaviorism Option D is incorrect because while private events are behaviors ABA focuses on environmental variables and observable behaviors for direct intervention rather than using private events as primary causal explanations