Normally, saying "every child HAS" would be absolutely correct.

But not in this case. Why?

This is because of the subjunctive verb form. When we have a verb like "demand" that denotes an order/recommendation, we have to use the subjunctive verb form.

What does this entail?
What follows "demanded" should be "that," then a new subject (in this case, "every child"), and then the infinitive form of a verb, but without the "to". Example: I demand that my daughter have vegetables.

Because the infinitive form of "has" would be "to have", we need "have" in the correct answer. Eliminate (A) and (C).

With the remaining answers, we have _____ and ______, so we have to have parallel structure.
(D) is the only one of the remaining answer choices that gives us the consistency we need with parallel structure: education and protection (i.e. NOUN and NOUN).

So right answer is (D).

Side note: There's another "face" of the subjunctive mood that involved hypothetical situations, but that will have to wait for another post.

93% of SC errors are just 6 types! This problem had 2 of those 6 types: Verb issues and Parallelism!