Final answer:
The 'Business purpose' is not a standalone doctrine used by the IRS to examine transactions for taxpayer abuse. Other doctrines include substance over form, step transaction, and economic substance, which scrutinize the real substance and economic significance of a transaction to prevent tax avoidance.
Step-by-step explanation:
The doctrine not used by the IRS to examine transactions for taxpayer abuse is D) Business purpose.
The doctrines commonly utilized by the IRS to challenge the tax consequences of a transaction based on its true substance include substance over form, step transaction, and economic substance. They are used when the IRS believes that a transaction is being reported in a way that does not reflect its actual substance. The substance over form doctrine allows tax consequences to be based on the substance of the transaction rather than its form.
The step transaction doctrine can collapse a series of formally separate steps into a single transaction to reveal its true intent and tax consequences. The economic substance doctrine requires the transaction to have economic significance beyond just tax benefits. Business purpose, however, is not a separate doctrine used to examine transactions but is a principle that may be considered as part of the economic substance doctrine to determine whether a transaction has a legitimate business reason aside from tax avoidance.