Final answer:
A low pH perm has the benefit of increased curl retention, making it preferred for maintaining healthy and well-defined curls. Hence option C is correct.
Step-by-step explanation:
The benefit of using a low pH perm is increased curl retention. Hence option C is correct. The pH level of a perm solution is a crucial factor that affects the outcome of the perming process. A lower pH indicates a more acidic solution.
In a low pH perm:
The disulfide bonds in the hair are broken and reformed more gently.
The hair cuticle remains more compact, reducing the risk of damage.
The curl pattern tends to last longer as the hair structure is better preserved.
While a low pH perm may take a bit longer to process compared to a higher pH solution, the increased curl retention and reduced risk of damage are considered advantages. Options a, b, and d are not typically associated with the benefits of a low pH perm.