No idea about the technicalities, but in an exam i would say C beacause:
A) I have no idea about the link between electronegativity and enthalpy
B) Is wrong
D)is true, but has nothing at all to do with these numbers- the question only talks about HCl and HI, not the actual formation reactions.
(I've had to do heaps of elimination type MC questions, MC really let me down last year)