Correct!
Sorry, your answer is incorrect. The correct answer is observational learning.
In negative reinforcement, a negative condition is removed in order to increase the probability of repeating a prior behavior. One might argue that the removal of social opprobrium is at work here, but that still wouldn’t explain the fact that the children mimicked the model’s behaviors prior to receiving any direct reinforcement.
Note that children’s behaviors may be positively reinforced after they engage in them, but their mimicry of the exact behavior of the models prior to any personal reinforcement best places this study as an example of observational (or vicarious) learning.
Classical conditioning refers to the connection of neutral stimulus to a naturally occurring stimulus (or unconditioned stimulus) in a stimulus-response pairing. There is no naturally occurring stimulus-response pairing on which to build in the study.