The standard Gibbs energy of formation (Δ_fG) is the:
a) Change in Gibbs energy for the formation of one mole of a compound from its elements in their standard states
b) Change in Gibbs energy for the formation of one mole of a compound from its elements in their natural states
c) Change in Gibbs energy for the decomposition of one mole of a compound to its elements in their standard states
d) The text does not provide information on the standard Gibbs energy of formation.