32x35=1,120
To solve this equation, all you have to do is put the two numbers in a calculator connected by multiplication sign,
-13 to 0 = 13 degrees changed. 0 to 22 is 22 degrees changed. 13 + 22 = 35 degree change.
10-3 = 7.
So there was a change of 35 degrees across 7 hours
35/7 = 5 degrees per hour.
B is the best strategy. (You mentioned an option D, but it's not shown in your question!!)