Rocks that make up the partially melted and are able to flow.

a) lithosphere.
b) asthenosphere.
c) inner core.
d) crust.

Rocks that make up the Asthenosphere partially melted and are able to flow.

Explanation:

Earth is made up of different layers. In the mantle, there are again different parts. One of the upper parts named asthenosphere just lies below  lithosphere.

The upper part of the asthenosphere is the zone where the lithospheric plates of earth's crusts moves. Due to the pressure and temperature of the conditions in the asthenosphere, the rocks become ductile which then moves at the rates of deformation.The flow is as a convection current which radiates heat away from the interior of the earth.