Step 1: Recall the Fact:
Look for the setting whose first job is looking after children for the day, not teaching them.
Step 2: Test each choice against this fact.
Choice 1 (Primary school): Here the focus is on schooling for children above about six years, so it does not suit a pre-school child needing care.
Choice 2 (Day care): The first purpose here is minding children through the working day while parents are away. That is exactly what the question describes, so it is right.
Choice 3 (Nursery school): Here the first purpose is preparing the child for school through play and activities, not full-day care, so it is not the best fit.
Choice 4 (Montessori school): This follows one educational method of learning through child-chosen activities. It is education led, so it is not the best fit.
Step 3: Cross-check the result.
Read the sentence once more with the chosen term in the blank. It should agree with the passage and with what is taught in the unit on early childhood care. Only one choice passes this test, and the other three each break one clear fact stated above. Each wrong choice names a different stage, place or person that does not match the clue in the question.
Final Answer:
The care-focused setting for pre-schoolers is day care, which is choice 2.
\[ \boxed{\text{Day care}} \]