Under the "Traditional Approach," the odd one out among the given account clarifications is (a) Building. The other options (b) Purchases, (c) Sales, and (d) Trade receivables are all related to the primary operations of a business, whereas building is a fixed asset that is not directly related to the revenue-generating activities of a company.

Explanation:

Traditional Approach refers to the method of accounting where transactions are recorded based on the double-entry system. In this approach, every transaction is recorded in two accounts, i.e., debit and credit. The debit entry represents what comes in, while the credit entry represents what goes out of the account. The following are the details of the given account clarifications:

(a) Building: A building is a fixed asset that is used to carry out business activities. It is a long-term asset that is not sold during the normal course of business. Its cost is capitalized and depreciated over time.

(b) Purchases: Purchases refer to the goods or services that a company acquires to sell or use in its operations. It is recorded as a debit entry in the purchases account.

(c) Sales: Sales refer to the revenue generated by a company by selling its goods or services to customers. It is recorded as a credit entry in the sales account.

(d) Trade receivables: Trade receivables refer to the amount of money that a company is owed by its customers for goods or services sold on credit. It is recorded as a debit entry in the trade receivables account.

Conclusion:

In conclusion, building is the odd one out among the given account clarifications under the Traditional Approach as it is a fixed asset that is not directly related to the primary operations of a business. The other options, i.e., purchases, sales, and trade receivables, are all related to the revenue-generating activities of a company.