The correct answer is C. Pia mater.
The pia mater is the innermost of the three meninges that surround the brain and spinal cord. It is a thin, delicate membrane that is closely attached to the surface of the brain and spinal cord. The pia mater is composed of a single layer of cells and contains a network of blood vessels that supply the brain and spinal cord with blood.
The dura mater is the outermost of the three meninges. It is a thick, tough membrane that is attached to the skull. The dura mater contains a layer of blood vessels that supply the meninges with blood.
The arachnoid membrane is the middle of the three meninges. It is a thin, delicate membrane that is located between the dura mater and the pia mater. The arachnoid membrane contains a space called the subarachnoid space, which is filled with cerebrospinal fluid.
The pleural membrane is a thin, serous membrane that lines the lungs and the inner surface of the chest wall. It helps to protect the lungs and to keep them moist.
I hope this helps!