Explanation:

- Option 1: Unreliable

- If there's an unjustified delay in recording a witness's statement, the reliability of their evidence could be questioned.

- Memory and details fade over time, which can affect the witness's accuracy.

- Option 2: Inadmissible

- "Inadmissible" refers to evidence not allowed in court.

- Delays in recording a statement alone might not make evidence inadmissible unless other factors affect legality.

- Option 3: Inadmissible and Unreliable

- A combination of both issues: evidence is neither credible nor legally permissible.

- Less likely as delays mainly affect reliability, not admissibility.

- Option 4: Only (b) and not (a)

- Suggests evidence is inadmissible but not unreliable.

- Doesn't consider the impact of delay on credibility.

Answer: Option 1 - Unreliable