Answer:
The correct answer is: 0°C + 0°C = 32°F
Step-by-step explanation:
We need to remember the conversion equation from Celsius to Fahrenheit:

In our case x = 0, then y will be:


Now 0°C + 0°C is just 0°C because if we add a body at a certain temperature to another body with the same temperature the total temperature will the same.
Then, knowing that 0°C = 32°F we can conclude that:

I hope it helps you!