Which is the best college major to choose STEM Fields?

I am a high school graduate and in dilemma of choosing my undergraduate major. I am sure about to go into STEM fields but I don't know which one to go for whether pure science, mathematics or any engineering field. I want to have maximum career flexiblity like I must be able to get into any technical or engineering or mathematics or pure science field later. So,can anyone please suggest me the college major?