Potassium (K), an alkali metal, and magnesium (Mg), an alkaline earth metal, both combine readily with bromine (Br), a halogen. What compound will each element (K and Mg) most likely form with bromine?

A.
KBr and Mg2Br

B.
KBr and MgBr

C.
K2Br and Mg2Br

D.
KBr and MgBr2