What is the formula of calcium nitride?

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

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

C.     \({\text{Ca(N}}{{\text{O}}_{\text{2}}}{{\text{)}}_{\text{2}}}\)

D.     \({\text{Ca(N}}{{\text{O}}_{\text{3}}}{{\text{)}}_{\text{2}}}\)

A