Final answer:
To prevent gingival recession, a full gold crown should replicate the normal contour of a natural tooth, which is crucial for gum health and to avoid irritation. Therefore, the correct option is C.
Step-by-step explanation:
To prevent gingival recession, a full gold crown should have normal contour reproduced. This means that the crown should mimic the shape and size of the natural tooth it replaces. Proper contouring is essential in maintaining the health of the surrounding gums and ensuring that the crown does not cause irritation or impede the natural cleaning processes of the mouth. An overcontoured tooth form may lead to plaque accumulation and gingival inflammation, while margins extended subgingivally could provoke chronic irritation and recession. A slightly narrow food table could compromise the function of the crown without necessarily protecting against recession.