When would it be appropriate to recognize a gain or loss on the abandonment or retirement of a well or individual item of equipment?

a. If the well or individual item of equipment constitutes a part of an amortization base

b. When a major abnormality occurs

c. When the DD&A is being computed on the basis of a cost pool that consists of a single reservoir or group of reservoirs relating to a single geological structural feature

d. When the abandonment constitutes a partial retirement

e. None of these apply