What is the formula of the ionic compound formed when calcium and nitrogen react together?

A.     ${\text{C}}{{\text{a}}_{\text{2}}}{{\text{N}}_{\text{3}}}$

B.     ${\text{C}}{{\text{a}}_{\text{3}}}{{\text{N}}_{\text{2}}}$

C.     ${\text{C}}{{\text{a}}_{\text{5}}}{{\text{N}}_{\text{2}}}$

D.     ${\text{C}}{{\text{a}}_{\text{2}}}{{\text{N}}_{\text{5}}}$

B