This is a FAFSA4caster question.
By selecting Yes you are indicating that your parents have filed an income tax return for the last calendar year. If your parents are now married (even if they were not married in the last calendar year) or are unmarried and both parents are living together, answer this question about them as a couple. If one parent filed an income tax return for the last calendar year and the other parent did not, answer Yes.
If they are not married and are not living together, answer this question about the parent for whom you are reporting financial information.