Under what circumstances can DD&A be computed on the basis of a single mineral despite the fact that oil and gas are jointly produced?

a. If the relative proportion of oil and gas extracted in the current period is expected to continue throughout the remaining productive life of the property

b. If the relative proportion of oil and gas extracted in the current period is expected to continue throughout the remaining fiscal year

c. If either oil or gas clearly dominates both proved and proved developed reserves

d. If either oil or gas clearly dominates the current production in both the current and past periods

e. None of these apply