The Asthenosphere Can Be Described as a Layer of the Earth's

The asthenosphere can be described as a layer of the Earth's interior:

A) within the crust that contains molten, flowing rock.
B) within the lithosphere that contains heat- softened, slow- flowing, but still- solid rock.
C) within the mantle that contains heat- softened, slow- flowing, but still- solid rock.
D) within the core that contains molten iron and nickel.