Before answering the question, you want to find the rate of change from one number to the next. To do that, you subtract the number one spot higher from the lower number. For example, 204.8 - 203= 1.8 206.6 - 1.8= 204.8
So, the rate of change is 1.8
So, if the boiling water at 1 thousand feet of altitude is 210.2, the boiling water at 0 thousands of feet of altitude is 212 because 210.2 + 1.8 is 212.
So the answer is the second one, 212.
I hope this helps:)