Final answer:
The parents are positively reinforcing the 2-year-old child's temper tantrums by giving in, making such behavior more likely to occur in the future as a result of operant conditioning principles in learning.
Step-by-step explanation:
When a 2-year-old child engages in frequent temper tantrums and the parents give in to the child's demands, the most correct statement among the provided options is that the parents are positively reinforcing the child's behavior. By giving in to the child's demands, the parents are rewarding the behavior, thus making it more likely to occur in the future. Reinforcement plays a key role in operant conditioning, which is a form of learning where behaviors are influenced by the consequences that follow them. In this case, the consequence (getting what they want) reinforces the child's tantrum behavior. From the perspective of behavior modification, it is essential to reinforce desirable behaviors rather than undesirable ones to encourage the development of socially acceptable behaviors over time.