The correct option is C Hygroscopic water
Water held tightly by soil particles around them is called hygroscopic water. It is held in a very thin film and is not available to plants. Plants are able to absorb capillary water which is present in the capillary spaces between soil particles. Run away water is also not available to plants. Field capacity denotes total water content in a field including hygroscopic water, capillary water and chemically bound water.