Final answer:
The correct answer is option a. A soft-curl permanent shouldn't be given to hair that is naturally straight, colored with henna, relaxed with sodium hydroxide, or fine and silky.
Step-by-step explanation:
A soft-curl permanent shouldn't be given to hair that is:
- Naturally straight: Soft-curl permanent involves chemically altering the hair's structure to create curls. Naturally straight hair has a different structure than curly hair, so it may not hold the curls well and could lead to a suboptimal result.
- Colored with henna: Henna is a natural dye that coats the hair, and it may interfere with the chemicals used in a soft-curl permanent. The interaction between henna and the perm chemicals could lead to unpredictable or undesirable outcomes.
- Relaxed with sodium hydroxide: Sodium hydroxide (lye) is commonly used in relaxers to straighten hair by breaking down protein bonds. Applying a soft-curl permanent on hair that has been previously relaxed with sodium hydroxide could cause damage or further weakening of the hair.
- Fine and silky: Fine and silky hair tends to be smooth and slippery, making it difficult for curls to hold. The structure of fine hair may not be suitable for a soft-curl permanent, as it requires more texture and body to hold the curls effectively.