Which of the following actions is considered an illegal move in wrestling?

Using a hold on the ankle or knee in wrestling can be considered illegal depending on the context and the way the technique is applied. The rules in wrestling are designed to ensure safety for all participants, and certain holds can place unnecessary strain on vulnerable joints, such as the knee and ankle. When a wrestler uses a hold that targets these areas, it may lead to injury, which is why such actions are typically classified as illegal moves.

In contrast, executing a takedown, targeting an opponent's head (when done within the rules), and performing a pin are all essential and permissible techniques in wrestling. These actions are fundamental to scoring points and achieving victory in matches while adhering to the overall sportsmanship and safety standards established by governing bodies.