This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Night guard bleaching refers to: 
Select and explain. 
A. Laser activated bleaching, B. Dentist prescribed home applied technique, C. Thermobleaching, D. Photo bleaching
B: Dentist prescribed home applied technique
Answer: B: Dentist prescribed home applied technique 
Explanation: Bleaching techniques 

For vital teeth 

– Home bleaching technique/night guard vital bleaching.
– In-office bleaching:
i. Thermocatalytic 
ii. Nonthermocatalytic 
iii. Microabrasion. 

For nonvital teeth 

– Thermocatalytic in-office bleaching 
– Walking bleach/intracoronal bleaching 
– Inside/outside bleaching 
– Closed chamber bleaching/extracoronal bleaching 

Laser-assisted bleaching.