When an asset is sold for more than its book value, the difference represents a gain or profit. According to the accounting equation, this profit increases the net income for the period, which subsequently increases the owner's equity. The total sale price is not added to equity; only the realized gain contributes to the increase in capital.

The Balance Sheet is fundamentally based on the Cost Concept (recording assets at historical cost) and the Accounting Equation Concept (Assets = Liabilities + Equity). While the Realisation and Matching concepts are critical for the Profit and Loss account, the Balance Sheet structure relies on the fundamental accounting equation and the cost basis for asset valuation.

The revenue recognition principle states that revenue should be recognized when it is earned, regardless of when the cash is actually received. This is a cornerstone of accrual accounting. Earning occurs when the performance obligation is satisfied, meaning the goods have been delivered or services rendered to the customer. This ensures that the financial statements reflect the economic activity of the period in which it occurred.

Capital represents accumulated wealth (a-2). A fund refers to a pool of money or assets (b-3). Circulating capital is capital that is turned over in the normal course of business to generate income (c-4). A flow represents a movement or change over a period of time (d-1).

A secret reserve, also known as a hidden reserve, is created when the actual value of assets is higher than what is reported in the balance sheet, or liabilities are overstated. Because these reserves are intentionally kept off the books to show a conservative financial position, they do not appear as a distinct line item on the balance sheet, unlike general or capital reserves which are explicitly disclosed.

Net Realizable Value (NRV) is often used in the 'lower of cost or market' rule. While historical cost is generally more objective, the source indicates NRV. This may be due to its relevance in conservative accounting practices where assets are not overstated.

The provision for doubtful debts is classified as a contra asset account because it reduces the gross value of accounts receivable to arrive at the net realizable value. It carries a credit balance, which offsets the debit balance of the accounts receivable asset account. By reporting this provision, the balance sheet provides a more accurate representation of the amount the company realistically expects to collect from its customers.

Liberal valuation often involves aggressive accounting that inflates current surplus. This allows the company to declare higher bonuses for current policyholders. However, this practice may deplete the reserves that should have been preserved for future periods, effectively benefiting current policyholders at the potential expense of future ones.

The practice of valuing inventory at the lower of cost or net realizable value is based on the Convention of Conservatism (or Prudence). Since this option is not listed, 'None of these' is the correct choice provided in the source.

When a policy document is lost, the policyholder does not need to seek a court order to obtain a duplicate. Insurers have established internal procedures to issue duplicate policies upon receiving an indemnity bond and proof of loss. This process is administrative and does not require legal intervention, provided the policyholder follows the insurer's specific requirements for replacement.