Which of the following is true?
A. Group 1 elements are more reactive than the group 2 elements because they have more valence to lose.
B.Lithium is the least reactive element in group, because its valence electron is held more tightly than the others in the same group.
C. Cesium is the active group metal, because its valence electron is held more tightly than the others in the same group.
D. The least reactive element in group 2 is the one with the largest atomic radium and the least amount of attraction between the nucleus and the valence electrons