Chronic Fatigue Syndrome (CFS) Is a Debilitating Disease of Unknown

Chronic fatigue syndrome (CFS) is a debilitating disease of unknown etiology that is estimated to affect 17 million people worldwide. In a case-control observational study, researchers identified DNA from a human gamma-retrovirus (XMRV) in 68 of 101 patients with CFS (67%) compared with 8 of 218 healthy controls (3.7%) . We want to know if these data show evidence of a relationship between XMRV and CFS. What is the value of the test statistic for this test?

A) x² = 2.2
B) x² = 14.6
C) x² = 80.2
D) x² = 154.1