Which of the Following Statements Is TRUE

Which of the following statements is TRUE?

A) If the N/Z ratio is too high, there are too many neutrons and the nuclide will convert a neutron to a proton via beta decay.
B) If the N/Z ratio lies somewhere below 1, the nuclide is stable.
C) If the 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) All stable nuclei have an N/Z ratio equal to 1.