Final answer:
The correct choice is 'c) Doctors' because they would be the professionals concerned with a polio patient's dietary restrictions during recovery.
Step-by-step explanation:
The context provided in the question about a girl wanting a milkshake while recovering from polio suggests a scenario where dietary and health restrictions are important for her recovery. Given the choices, the most relevant collective who would be concerned about the nutritional aspects of a patient's diet, especially during a period of illness, would be c) Doctors. When it comes to diseases such as polio, which can have significant health repercussions, doctors often recommend specific diets to aid in recovery and to avoid complications. In this case, it seems that the doctors might not have liked the patient having a milkshake because it might not have been suitable considering her health condition.