1 – Correct
The last line of the texts suggests that only those who have committed crimes will commit sexual and violent crimes in the future and hence, only the DNA of those who have committed crimes should be kept. It does not take into account that some cases of sexual and violent crimes are first offences.
2 – Correct
The argument is that only the DNA of criminals should be kept because only they will commit sexual and violent crimes in the future. However, if a person is found not guilty and actually, they have committed it, then their DNA should be kept according to the writer’s logic.
3 – Wrong
It does not matter how the crimes are solved. According to the writer’s logic, criminals’ DNA should be kept regardless.
Since statements 1 and 2 are correct, D is the answer.