1 – Correct
If a lot of re-offenders are being sent to prison, this would definitely cause the decline to occur.
2 – Correct
If a lot of the original offenders die, this would cause the decline to occur.
3 – Correct
Harsher sentencing would prevent some of the original offenders from doing any more offences, causing the decline to occur.
Since all statements are correct, G is the answer.