Which one of the following is not a generally accepted accounting principle:

A. Sales, revenues and incomes should not be anticipated or materially overstated

B. There must be proper cut off accounting for inventories and liabilities for costs and expenses

C. Non-recurring and extraordinary gains and losses should be recognised in the period they accrue, but should be shown separately from the usual operations

D. Long-term investments in securities should ordinarily be carried at market quotations

Answer: Option D