An International Study of Hypertension by Wolf-Maier Et Al

An international study of hypertension by Wolf-Maier et al. (2003) found that:

A) More Europeans than Canadians and Americans had hypertension
B) More Canadians and Americans than Europeans had hypertension
C) Approximately the same proportion of Europeans and Americans and Canadians had hypertension
D) None of the above; international comparisons could not be made due to differences in the methods of measurement