List the three things antin perceived free in America? And which of these did she regard as most important?

Free Lights Free Music Free Education

Mary Antin considered free education as the most important thing.

Explanation:

Mary Antin (1881-1949) was a Russian Jew immigrant who in 1894 immigrated to America along with his parents and siblings. She in her immigrant autobiography "The Promised Land" talks about her own and her family's initial experiences as immigrant settler in Boston's West End slum.

She talks about three things which were free then in America in contrast to Russia, these three things are;

Free Lights: "Light was free; the streets were bright as a synagogue on a holy day."

Free Music: "Music was free; we had been serenaded, to our gaping delight, by a brass band of many pieces soon after our installation on Union Place."

Free Education: "Education was free. That subject my father had written about repeatedly, as comprising his chief hope for us children"

She talks about free education the most and considers it the most important free facility as displayed by her words, "the essence of American opportunity, the treasure that no thief could touch, not even misfortune or poverty. It was the one thing he was able to promise us when he sent for us; surer, safer than bread or shelter."