If a foster child says his caregiver is hitting him, you must immediately:

When a foster child makes an allegation of abuse, it is important to take action immediately to ensure their safety and well-being. Options A and D are incorrect because they require inaction or delay, which can potentially put the child at further risk. Option C is incorrect because discussing the matter with the caregiver first could potentially jeopardize the investigation and also put the child at risk for retaliation. Therefore, option B is the correct answer as it is the most appropriate and responsible course of action in this situation.