The author mentions each of the following as possible contributing causes to reversals of the Earth's magnetic field ...

At first I selected D because no where is the passage are circulation patterns mentioned. However, from answer choice B, temperatures on earth’s surface are not explicitly stated either. Since redistribution is similar to circulation, I assumed D had support and selected B. How does D have support and B doesn’t when neither is explicitly stated? I was trying my best not to assume things like advised.