Which of the Following Steps in Purine Biosynthesis Are Regulated $\rightarrow$

Multiple Choice

Which of the following steps in purine biosynthesis are regulated by feedback inhibition by ADP and GDP?
I. ribose-5-phosphate $\rightarrow$ PRPP
II. PRPP $\rightarrow$ 5-phosphoribosame
III. glycine ribonucleotide $\rightarrow$ formylglycinamide ribonucleotide
IV. FAICAR $\rightarrow$ IMP
V. IMP $\rightarrow$ adenylosuccinate

A) I only
B) I and V only
C) II, III, V
D) I and II
E) IV and V