The number of respondents who actually participate in a research project is described as: (A) actual subjects (B) real sample (C) net incidence (D) filtered public Correct Ans: (B) Explanation:Researchers define the number of respondents who participate in a study as the real sample. This term refers to the actual participants who contribute data to the research. Other options like "actual subjects," "net incidence," and "filtered public" are incorrect. "Actual subjects" is too broad and doesn't focus on participation. "Net incidence" measures frequency, not participation. "Filtered public" refers to a subset of people, but not those who actively participate in the study. Therefore, the correct answer is real sample.