The Standard Enthalpies of Formation of Various Iodine Species Are

The standard enthalpies of formation of various iodine species are as follows:
Substance
ΔH°_f (kJ/mol)
I(g)
+107
I₂(g)
+21
HI(g)
+26
What additional information is needed to calculate the standard enthalpy change of the following reaction?
H₂(g) + I₂(g) → 2HI(g)

A) none,because the answer is 2 times 26 kJ/mol
B) the enthalpy of formation of I−(g) and H+(g)
C) the enthalpy of formation of solid iodine
D) none,because the enthalpy of formation of I₂(g) and HI(g) are given and the enthalpy of elemental hydrogen is zero
E) the enthalpy of formation of gaseous hydrogen