Answer:
The oldest is section A, and the newest is section B.
Explanation:
First of all, the bottom most layer is almost always the oldest, because when rocks form, they don't go "hey lemme form under you", they form on top.
Second, bottom most layer is has the simplest fossils and the fossils are the same. You can see that as the higher section you go, the fossils are more complex and have more variety. Which is because of evolution.
Third, I don't know if this counts, but the bottom has the least color so I'm guessing that means that it has been decaying and whatever else you wanna call it than the other layers. Whereas the top is the most colorful, in my opinion.
