table A from 2-3 minutes it rose 64.9-61.3 = 3.6
from 3-7 it rose 79.3 -64.9 = 14.4 = 3.6 degrees per minute
Table B needs to raise faster than 3.6 per minute
64.4 -61 = 3.4
64.6 - 61 = 3.6
64.3 -60.6 = 3.7
so the 3rd table is correct