Part may be to see if they are your safety.
Don’t overthink it. My answer when I applied was:
“I’m applying to schools that offer X, Y, and Z, such as AA, AB, and AC,” where two of the schools are at the same level as the school asking the question, and the third is a step below. I would not list all the schools, and I would list them in random (or alphabetical) order. Since some schools ask this question to predict yield, you do not want to reveal to a school that it is your safety (if it is in fact a safety).