Final answer:
The correct answer is Sodium Hydroxide. It can cause severe damage to hair that has been previously permed with ammonium thioglycolate.
Step-by-step explanation:
The correct answer is A. Sodium Hydroxide.
Sodium hydroxide, also known as lye or caustic soda, is a strong alkaline compound that can cause severe damage to hair. When applied to hair that has been previously permed with ammonium thioglycolate, it can lead to excessive breakage and damage.
Coconut oil, lemon juice, and aloe vera gel are all safe to use on hair that has been previously permed with ammonium thioglycolate.