Final answer:
The Latin term indicating that a person is not of sound mind is 'Incompetence', which means they are legally incapable of managing their own affairs. A learning disability is characterized as a neurological disorder that affects the brain's information processing abilities.
Step-by-step explanation:
The Latin term signifying that a person is not of sound mind and therefore legally incompetent to manage their own affairs is d) Incompetence. This legal term is often used in contexts where an individual's mental capacity is called into question for making decisions related to their personal care, finances or legal matters. Incompetence implies that a person lacks the ability to make informed decisions due to mental disabilities or impairments.
Regarding the question about a learning disability, it is defined as b) a neurological disorder. Learning disabilities are a group of disorders that affect a person's ability to either interpret what they see and hear or to link information from different parts of the brain. These limitations can show up in many ways — as specific difficulties with spoken and written language, coordination, self-control, or attention. Such disorders are intrinsic to the individual and presumed to be due to central nervous system dysfunction.