Final answer:
To preserve moisture and maintain the curls after a soft curl perm, cosmetologists recommend clients wear a processing cap while sleeping and avoid shampooing the hair within the first 24 hours. The correct option is C.
Step-by-step explanation:
After a soft curl perm, cosmetologists generally recommend that clients should avoid shampooing the hair within the first 24 hours to allow the hair to fully set. This is critical because washing too soon can deactivate the perm's chemicals before they have finished processing and thus can lead to a weaker or uneven curl pattern.
Instead of shampooing, to preserve moisture and maintain the perm, other steps can be taken such as using a leave-in conditioner, but the correct answer to the question is wearing a processing cap while sleeping. This helps minimize friction on the hair while sleeping and can help maintain the integrity of the curls and moisture of the hair.
This is more effective than applying base cream before showering or staying indoors during the sunniest part of the day, as those steps do not directly contribute to maintaining the moisture in a freshly permed hairstyle.