Which of the Following Statements Are True

Which of the following statements are true?

A) If N/Z ratio is too high,there are too many protons and the nuclide will undergo positron emission or electron capture.
B) If N/Z ratio lies somewhere below 1,the nuclide is stable.
C) If N/Z ratio is too low,there are too many neutrons and the nuclide will undergo beta decay.
D) The valley of stability is the geographic location where many of the known nuclides were first discovered.
E) None of the above are true.