Explanation:

- Option 1: Must be total

- For unsoundness of mind to exempt someone from criminal liability, the impairment must completely inhibit the ability to understand the nature of the act or the fact that it is wrong.

- A total lack of cognitive function is typically required to escape liability.

- Option 2: Must be partial

- A partial impairment suggests some understanding or control remains.

- This generally does not fully exempt someone from liability because some cognitive faculty is intact.

- Option 3: Both (a) & (b)

- Suggests that either total or partial impairment can exempt liability.

- Typically not correct in legal terms, as full impairment is usually needed.

- Option 4: None of the above

- Would imply conditions outside of the listed options.

- Not generally applicable to escape liability based on common legal standards.

Option 1: Must be total is the correct answer. ""