according to the leading research findings on academic achievement which of the following has the greatest influence on a student's success in school

The correct answer to this open question is the following.

According to the leading research findings on academic achievement, what has the greatest influence on a student's success in school is the parent's socioeconomic status.

Education is not cheap. It has increased the price of college. Most students have to apply for financial aid and some others, aspire to an academic scholarship or an athletic scholarship to get access to quality education. That is why some researchers have concluded that the parent's socioeconomic status has the greatest influence on a student's success in school because, in today's education environment, the support of the parents is vital in order to cover all expenses and difficulties a student lives on campus.

I think the answer to the question is high school