In a case where a child discloses abuse by a parent and the medical exam shows signs of abuse, an appropriate plan might be to:

The most appropriate plan in this scenario, where a child has disclosed abuse by a parent and medical examinations confirm signs of abuse, is to remove the child. This is a critical action as it prioritizes the immediate safety and well-being of the child. In cases of alleged abuse, ensuring the child is in a safe environment is paramount, particularly when there's evidence supporting the child's disclosures.

Removing the child from the home can prevent further harm and allows for an evaluation of the situation, providing time to investigate the abuse claims and to explore protective and support services for the child. Meanwhile, this action enables professionals to work with the family dynamics while safeguarding the child's physical and emotional health.

The other options, while they can be relevant in certain situations, do not address the immediate safety concern as directly as removing the child does. Asking the father to leave or arresting him might not be effective in ensuring the child's safety until the situation is fully assessed. Charging the mother with failure to protect is a more complex legal step that may occur later in the process, after investigations are concluded and if warranted. Overall, the priority in child welfare cases is always the safety of the child, making removal the most suitable immediate response.