The statement that best supports the author;s claim is: "Parents are supportive of public schools adopting school uniforms for several reasons; the most common being affordability." (last option)
In the passage the author claims that "(...) uniforms allow students and their parents to save money (...)". The author explains that parents spend money on uniforms at the beginning of the year, but such investment would be much greater if students had to wear their own clothes to school.