Answer:
Hey there,
The answer is A.
This is because the crust is broken into parts called plates and these plates collide with each other or separate from each other or slide past each other.
They move because they sit on top of semi molten rock in the mantle. The semi molten rock moves due to convection currents which is heated up by the core.
It’s is not option B because it does not have u form thickness through out it. For eg the continental crust is 60 km thick while the oceanic plates are wonly 10km thick.
It is not C as the mantle is semi molten not solid.
And it’s not D because it’s not a single layer but multiple layers.
So A is the answer.
I hope this helps!
Step-by-step explanation: