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: