Answer:
C. mg and Ca
Step-by-step explanation:
These chemical elements are collectively called as the Alkaline Earth Metals. Calcium and Magnesium are two of the six elements that fall into this category. The outer electronic structure of all these elements is similar due to which they all have similarity in their chemical and physical properties. They are all shiny, though fairly soft but still harder than alkali metals. Further, these are usually white or silvery coloured elements.They react with water to form hydrogen gas and metal hydroxide and with oxygen, they form oxides.