The correct statement with respect to the above pair of reactions are that
(I) the reactions are stereospecific
(II) (X) is erythro and (Y) is threisomer
(III) (X) is threo and (Y) is erythro isomer
(IV) each of (P) and (Q) gives a mixture of (X) and (Y)
A. I and II
B. I and III
C. I and IV
D. II and IV