A study is conducted to evaluate the onset and course of cardiovascular disease in African American men and women in the USA. Census data from the year 2000 are used to select the study sample. A series of factors including family income and years of education is defined. Census data most representative of the national census data for the factors selected are used for sampling.Which of the following best describes this sampling technique?
A. Blocked randomization B. Population-based C. Sample of convenience D. Self-selection E. Sequential