Respuesta :

I am pretty sure that  the following which correctly completes the following equation is : Nitrogenous base + sugar + phosphate group = Nucleoside. Just according to the main poins of its definition you can easily assure yorself it is correct, as Nucleotide is an organic compound which is made from of nitrogenous base, a sugar, and a phosphate group. 
Do hope it will help you! Regards.

A. Nucleotide is the correct answer