**Not a Business Transaction: Paid 20000 towards son's fees from personal bank account**

Business transactions are financial activities that involve the exchange of goods, services, or money between a business and its stakeholders. These transactions are recorded in the books of accounts and have a direct impact on the financial position of the business. However, not all transactions are considered business transactions. In the given options, the transaction of paying 20000 towards the son's fees from a personal bank account is not a business transaction.

**Explanation:**

To understand why this transaction is not a business transaction, let's analyze the characteristics of a business transaction:

1. **Exchange of Goods or Services**: In a business transaction, there is an exchange of goods or services between the business and its stakeholders. This can include the purchase of assets, payment for services rendered, or the sale of goods.

2. **Influence on Business Entity**: Business transactions have a direct impact on the financial position of the business entity. These transactions are recorded in the books of accounts and are used to prepare financial statements, analyze profitability, and make informed business decisions.

Now let's consider the transaction mentioned in option C: "Paid 20000 towards son's fees from personal bank account."

- This transaction does not involve the exchange of goods or services between the business and its stakeholders. It is a personal expense incurred by an individual for his son's education.

- The payment made from a personal bank account indicates that it is not related to the business entity. Personal expenses should not be mixed with business expenses as it can lead to inaccuracies in financial reporting and taxation.

- As this transaction is not a business transaction, it should not be recorded in the books of accounts or included in the financial statements of the business.

In conclusion, the transaction of paying 20000 towards the son's fees from a personal bank account is not a business transaction. It is a personal expense that should be kept separate from the business entity's financial records. It is important for businesses to maintain clear and accurate financial records to ensure transparency, compliance, and effective decision-making.