An analyst gathers the following information about two well-diversified portfolios in an economy satisfying a one-factor arbitrage pricing theory model:

| Portfolio | Expected Return | Factor Sensitivity |

|-----------|------------------|---------------------|

| X | 8.0% | 0.8 |

| Y | 16.0% | 2.4 |

The expected returns reflect a 1-year investment horizon and all investors agree on the expected returns of these portfolios. The return on the risk-free asset is closest to: