For Gaseous Hydrogen Atoms at 298 K Is +217 $\rightarrow$ H₂(g)
B)½H₂(g)

For gaseous hydrogen atoms at 298 K is +217.kJ.mol^-1 ,the standard enthalpy of formation can be best written as:

A) 2 H(g) $\rightarrow$ H₂(g)
B) ½H₂(g) $\rightarrow$ H(g)
C) H₂(g) $\rightarrow$ 2 H(g)
D) 2 H₂(g) $\rightarrow$ 4 H(g)
E) H(g) $\rightarrow$ ½H₂(g)