The correct answer is: c. heavy gradation
When the line of inclination is very close to the head, it is referred to as "heavy gradation." This terminology is commonly used in the context of haircutting and hairstyling, where the angle and position of the cutting tool relative to the hair can vary to achieve different effects. Heavy gradation typically involves cutting the hair very close to the head, resulting in a dramatic and noticeable change in length or texture.