What is the name of Earth's innermost layer?

A. core

B. crust

C. geosphere

D. mantle

A.) Core

Explanation:

Core definition: a central and often foundational part usually distinct from the enveloping part by a difference in nature.

The correct answer is option A. core.

Explanation:

The core is the innermost layer of the earth. It is a very hot, dense center of the earth that is beneath the solid mantle and crust that are cold. It is a solid ball that has about a 3485-kilometer radius.

The core of the earth is very hot regions which are said to be because of radioactive decay of different elements.

Thus, the correct answer is option A.