ANS:C - capital

The enlarged head of a supporting column in a flat slab, technically known as a "capital," serves several important functions in the structural system:

1. Load Distribution: The primary function of a capital is to distribute the load from the slab or beam above more evenly onto the supporting column below. By enlarging the contact area between the slab and the column, the capital helps to reduce the intensity of stresses and prevent localized failures.
2. Increase Bearing Area: The widened top portion of the column provided by the capital increases the bearing area available to support the load transferred from the slab. This helps to minimize the risk of crushing or failure of the concrete at the column-slab interface.
3. Improved Aesthetic Appearance: Capitals are often designed with architectural considerations in mind to enhance the visual appeal of the structure. They can add decorative elements and architectural detailing to the top of the column, contributing to the overall aesthetics of the building.
4. Structural Integrity: By providing additional support and reinforcement at the critical junction between the column and the slab, capitals help to improve the overall structural integrity and stability of the building. They reduce the risk of premature failure or damage to the structural elements.