Final answer:
The risk premium on the market portfolio is 11.5%.
Step-by-step explanation:
The risk premium on the market portfolio can be calculated using the formula:
Risk Premium = Expected Return - Risk-Free Rate
In this case, the expected return on Karol Co. stock is 16.5% and the risk-free rate is 5%. Therefore, the risk premium on the market portfolio is 16.5% - 5% = 11.5%.
Therefore, the correct answer is D) 10.0%.