The correct answer is (b) 15.03%.
The average return is calculated by dividing the total return by the total investment. In this case, the total return is 3 * 10000 = 30000. The total investment is 40000 + 50000 + 80000 = 170000. Therefore, the average return is 30000 / 170000 = 17.65%. However, this is not the correct answer because the question asks for the average return from three securities, not the total return.
To calculate the average return from three securities, we need to calculate the return for each security and then average them. The return for each security is calculated by dividing the dividend by the investment. In this case, the returns are 10000 / 40000 = 25%, 10000 / 50000 = 20%, and 10000 / 80000 = 12.5%. The average return is then 25% + 20% + 12.5% / 3 = 15.03%.
Therefore, the correct answer is (b) 15.03%.