The correct answer is option D) asthenosphere.
The magma chamber is found in the asthenosphere, which is the upper layer of the mantle. The asthenosphere is a semi-solid layer that is less dense than the surrounding rock, which allows it to flow slowly. As the asthenosphere flows, it drags the overlying lithosphere (the crust and upper mantle) with it. This movement of the lithosphere is what causes plate tectonics.
Magma chambers are formed when hot molten rock (magma) rises from the mantle and pools beneath the crust. Magma chambers can be found at a variety of depths, but they are most commonly found in the asthenosphere. Magma chambers can be very large, and they can contain millions of cubic kilometers of magma.
When the pressure in a magma chamber becomes too great, the magma can erupt to the surface, forming a volcano. Magma chambers can also slowly cool and solidify, forming intrusive igneous rocks such as granite and gabbro.
Therefore, the correct answer is option D) asthenosphere.