The innermost part of the Earth is called the core. The Earth is made up of several layers, and each layer is different in terms of material, temperature, and density.

The main layers of the Earth are:
- Crust: This is the outermost layer, where we live. It is very thin compared to the other layers.
- Mantle: Found below the crust, this layer is made of solid and molten rock. It’s where magma comes from during volcanic eruptions.
- Core: This is the deepest and hottest part of the Earth. It is divided into two parts: the outer core (liquid) and the inner core (solid). The core is mostly made of iron and nickel.

The inner core is extremely hot, with temperatures as high as the surface of the sun. Even though its very hot, the inner core remains solid because of the immense pressure at that depth.

Let’s review the options:
- Crust is the top layer, not the innermost.
- “Mental” seems to be a spelling error for “mantle,” which is the middle layer.
- Core is the correct answer. It lies at the center of the Earth.
- None of these is incorrect because "core" is listed.

So, the correct answer is: Core.