Final answer:
Calvin should evacuate with his family immediately due to the severity of the incoming Category 5 hurricane, securing essential items and leaving the city to find safe accommodation.
Step-by-step explanation:
When a Category 5 hurricane is predicted to make landfall in 48 hours, Calvin should prioritize the safety of his family by following a clear and responsible evacuation plan. Immediate evacuation is the most suitable action, particularly with a storm of such magnitude, where staying behind could put lives at serious risk. The high intensity of a Category 5 storm can lead to catastrophic damage, with sustained winds of over 157 mph capable of destroying houses, uprooting trees, and causing severe flooding. The priority should be to gather his family, secure important documents and essentials, and promptly leave the city to find a safe location away from the path of the hurricane.
Piling sandbags is ineffective against the storm surge likely associated with such a powerful hurricane, and sheltering in the highest part of the house is dangerous due to potential roof failure. Boarding up windows might protect the home from some damage by flying debris, but it is not sufficient to ensure safety. The safest plan of action aligns with the final answer: C. gather his family, immediately evacuate his home, and leave the city.