Final answer:
During the cornrow hair braiding process, the hair underneath the previous row needs to be properly detangled to ensure a neat hairstyle and prevent hair breakage.
The correct answer is option C) Detangled.
Step-by-step explanation:
When engaging in the cornrow process, it is important that the hair directly underneath the previous row is detangled. This ensures the braids are neat and the tension is distributed evenly throughout the hairstyle. Thus, during the cornrow process, when picking hair at the base, the hair directly underneath the previous revolution must be C) Detangled. This step is essential to prevent breakage and to maintain the health and appearance of the cornrowed hair.