In Considering Interim Financial Reporting, How Did the Accounting Principles

In considering interim financial reporting, how did the Accounting Principles Board conclude that such reporting should be viewed?

A) As a "special" type of reporting that need not follow generally accepted accounting principles.
B) As useful only if activity is evenly spread throughout the year so that estimates are unnecessary.
C) As reporting for a basic accounting period.
D) As reporting for an integral part of an annual period.