Final answer:
The Earth's core at a depth of 3500 km is composed of a liquid outer core made mostly of iron and nickel, surrounding a solid inner core. The correct option is D.
Step-by-step explanation:
At a depth of 3500 km within Earth's interior, it is believed to exist a layer consisting mostly of iron and nickel, which is the Earth's core. The core can be subdivided into two distinct parts: the liquid outer core and the solid inner core. This layer is not solid rock and high pressure minerals, molten lava and magma, or a layer of liquid water.
At 3500 km, we would be within the liquid outer core which surrounds the solid inner core, influencing the creation of the Earth's magnetic field.
Hence, Option D is correct.