The correct answer is outer core. Important Notes: • The interior of the earth is divided into three parts namely Crust, Mantle, and Core. • The core is the innermost layer of the earth. • The radius of the innermost layer(core) is about 3500 km. • The core is made up of material constituted by nickel and iron. • The temperature and pressure of the central core are very high. Explanation & Key Takeaways: • The core is further subdivided into two layers called the outer core and inner core. • The outer core of the earth is in a liquid state. • The inner core is in solid-state • The outer core is responsible for the earth's magnetic field. Related Concepts: • The crust is the outermost of the earth. • It is brittle in nature. • it the thinnest layer of Earth. • The thickness of the crust varies under the oceanic and continental areas. • The mantle is the second layer in the interior of the earth. • The mantle extends from Moho’s discontinuity to a depth of 2,900 km. • The upper portion of the mantle is called the asthenosphere.