What are the formulas,names,and molecular masses of the compounds obtained during the estimation of phosphorus in organic compounds?

• A
  Magnesium pyrophosphate ($Mg_{2}P_{2}O_{7}$,$222 \ g/mol$) and Ammonium phosphomolybdate ($(NH_{4})_{3}PO_{4} \cdot 12MoO_{3}$,$1877 \ g/mol$)
• B
  Magnesium phosphate ($Mg_{3}(PO_{4})_{2}$,$262 \ g/mol$)
• C
  Phosphoric acid ($H_{3}PO_{4}$,$98 \ g/mol$)
• D
  Phosphorus pentoxide ($P_{2}O_{5}$,$142 \ g/mol$)