50. How many of the following statements are false? I: the Group 3A elements are all metals, II: alkaline earth metals react less vigorously with water than do alkali metals, III: salts can consist of hydrogen, IV: because Li is the strongest reducing agent among the alkali metals, it reacts most quickly with water of the alkali metals (A) 0 (B) 1 (C) 2 (D) 3 (E) 4