Final answer:
The option 'c. 16 year old patient' is the exception to legal practices when obtaining informed consent since individuals under the age of 18 generally cannot give legal consent, with certain exceptions.
Step-by-step explanation:
The exception to legal practices when obtaining informed consent from a patient is 'c. 16 year old patient'. In general, individuals under the age of 18 are considered minors and are not legally able to give informed consent. There are however exceptions to this rule, such as in cases of emancipated minors or situations where minors are allowed by law to consent to certain types of medical care. A competent adult, a person who is 25 years old, and an emancipated minor all have the legal capacity to provide informed consent. It is critical to ensure that all patients understand the implications and consequences of their medical decisions, and this understanding is captured through the process of informed consent.