21. An analyst gathers the following information on three well-diversified funds, where the returns and tracking errors are based on a five-factor macroeconomic model:

| Fund | Fund Return | Benchmark Return | Tracking Error |

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

| X | -1.5% | -4.5% | 1.2% |

| Y | 3.2% | 1.8% | 0.8% |

| Z | 2.3% | -0.9% | 1.6% |

The fund with the most favorable information ratio is: