In Purine Biosynthesis, Which Steps Require the Participation of Tetrahydrofolic

In purine biosynthesis, which steps require the participation of tetrahydrofolic acid?

A) formation of phosphoribosylamine and glycinamide ribonucleotide
B) formation of alpha-N-formylglycinamide and 5-aminoimidazole-4- carboxamide ribonucleotide
C) carbon dioxide fixation forming 5-aminoimidazole-4-carboxylic acid and inosinic acid
D) formation of N-formylglycinamide ribonucleotide and 5-formamidoimidazole-4-carboxamide ribonucleotide
E) formation of inosinic acid and adenylosuccinic acid