It is not enough to make vaccines against childhood diseases available

Even i have same question , i was stuck between D and E, but chose D,

Why not D, to require is subjective verb require/always preceded by to

correct me if i m wrong

It is not enough to make vaccines against childhood diseases available; experience shows that it is also necessary for local governments to enact regulations requiring that children should be immunized before they attend school.

A. requiring that children should be immunized- should be is not required as there should not be any modal verb(could, should,etc) before the bare verb.
B. that require children's being immunized- Incorrect use of the word children
C. which require the immunization of children- Doesn't comply with the rule of Subjunctives.
D. to require immunization of the children- It doesn't sound correct.
E. requiring that children be immunized- Any helping verb should be removed, it is perfectly done in this sentence.

Official Answer:- Option E.

Thanks!


Regards,
Raunak Damle!