Concept:Field capacity refers to the moisture left in the soil after excess water has drained away by gravity.
Explanation:When the soil is saturated, gravitational water drains downward through large pores until drainage stops.
The point at which this drainage ceases is called field capacity.
At field capacity, capillary water remains held in the small pores of the soil.
Capillary water is held by surface tension forces, but it is still loose enough for plant roots to absorb it.
Hygroscopic water, however, forms a very thin and tightly bound film around soil particles, making it unavailable to roots.
Gravitational water moves too quickly and superfluous water is simply excess water in the soil.
Thus, the water that is available for root absorption at field capacity is capillary water.
Answer:A. capillary water