The water readily available to plants for absorption by roots is

Capillary water is the water held by micropores of soil. This water is available for the plant because it gets trap in soil solution near the root of the plants. And some water is retained in mineral salts by chemical bonds but it does not increase the absorption capacity of roots. This is called chemically combined water. Thus the only water available for the plant is capillary water so the correct option is C.