Final answer:
The nurse should immediately assess the child's history of fluid intake to determine the level of dehydration or underlying cause for the lack of urinary output and other present symptoms.
Step-by-step explanation:
The question pertains to a 2 year-old child who has presented in the emergency department with a potentially serious condition, indicated by an absence of urine output (anuria) for a day and pale appearance. The immediate assessment to be carried out by the nurse should focus on History of fluid intake (Option C). This involves inquiring about how much fluid the child has consumed, when the last fluid intake was, and the types of fluids ingested. This information is crucial for determining the child's hydration status and the potential need for fluid resuscitation. Additionally, the nurse should be assessing the child's overall condition, including vital signs, skin turgor, mucous membranes, and capillary refill time to evaluate for signs of dehydration or shock.