This scenario best represents positive automatic reinforcement.
In this context, Georgina's recognition of her muscle definition and her pride in her strength training efforts result in a positive feeling that reinforces her behavior (strength training). She experiences intrinsic motivation and satisfaction from her progress, which encourages her to continue engaging in that behavior. There's no external social reinforcement mentioned (like praise from others), so it's not social reinforcement. It's also not negative reinforcement, as there’s no indication of removing an unpleasant stimulus. Thus, it aligns most closely with positive automatic reinforcement.