Can someone please give me input on this

Question

question?

Complete immunization is usually
required of chldren:

1.who will be turning 2 years old.

2.before they can travel across
state line.

3.at the time they enroll in
childcare programs.

This question is confusing because
when children enroll in childcare
programs there immunizations are
not usually complete. They only
have had a minimum of immunizations.
So, how can they be complete?
But, this is the question on my test.
So, should I put #3 as my answer?

Yes. Number 3 is the best answer. At the time they enroll in a child care program, their immunizations should be complete -- for their age.