The correct answer is (a), (c) only.

Let's analyze each statement:

Statement (a): The risk element keeps a business person vigilant and going.

This statement is true. Risk is an inherent part of any business venture. Business owners need to be vigilant and proactive in managing risk in order to succeed.

Statement (b): All businesses guarantee for return of principal amount invested or profit.

This statement is false. No business can guarantee a return on investment. There is always some degree of risk involved in investing in a business, and there is no guarantee that the investor will get back their money or make a profit.

Statement (c): One time transaction is not business.

This statement is true. A business is an ongoing activity that involves the exchange of goods or services for money. A one-time transaction, such as selling a used car, is not considered a business.

Statement (d): A business can involve goods services purchased for self-consumption.

This statement is false. Businesses do not typically purchase goods or services for self-consumption. They purchase goods or services to sell to others or to use in the production of other goods or services.

Statement (e): Dividend is the reward for undertaking a business activity.

This statement is not true. A dividend is a distribution of profits to shareholders of a corporation. Shareholders invest money in the corporation with the expectation of receiving a return on their investment in the form of dividends.

Therefore, the only statements that are true are (a) The risk element keeps a business person vigilant and going and (c) One time transaction is not business.