Final answer:
When applying a prophy cup full, all of the teeth in a person's mouth are typically cleaned.
Step-by-step explanation:
When applying a prophy cup full, it is important to consider the number of teeth that need to be cleaned. A prophy cup is a dental polishing instrument that is used to remove plaque and stains from the teeth. The question asks how many teeth are involved when applying a prophy cup full, and the correct answer is C) Full arch. This means that when using a prophy cup, all of the teeth in a person's mouth are typically cleaned.