请教gwd-20-3 急，考试在即了

Q3:

The state has proposed new rules that would set minimum staffing levels for nurses, rules intended to ensure that at least one nurse is assigned for every four patients put through triage in a hospital emergency room.

1. rules intended to ensure that at least one nurse is assigned for every four patients put through triage in a hospital emergency room
2. rules with the intent of ensuring one nurse at least to be assigned for every four patients to be put through triage in a hospital emergency room
3. rules intending to ensure at least one nurse is assigned for every four patients in a hospital emergency room put through triage
4. with the intent of ensuring that at least one nurse should be assigned for every four patients in a hospital emergency room that are put through triage
5. and this is intended to ensure one nurse at least to be assigned for every four patients put through triage in a hospital emergency room

   逗号前面已经是一个完整的句子，如果rules后面用intended不就是又一个完整句子了？个人认为对rules修饰的话用intenting 吧。晕了，望有能人帮我解释一下！感谢！Answer: a