Large Circulation Patterns in the Sun, Dubbed "Conveyor Belts," That

Large circulation patterns in the Sun, dubbed "Conveyor Belts," that transport material fromthe equator to the poles, then back to the equator at a depth of 300,000 km, take how long tocomplete a cycle?

A) less than a day
B) a few years
C) a few decades
D) a few centuries
E) tens of millions of years, comparable to the convection cycle in Earth's mantle