<prompt> In the question, data has been divided into two groups, i.e. HIV positiveHIV negative Data should be measured on nominal scale especially Dichotomous type of nominal scale.Interval scale dataOrdinal scale dataCategorical dataNone  <response>: Ans. is c i.e., Categorical data Blood group is a qualitative Categorical data. Blood group are divided into qualitative categories A, B, AB, 0 -3 Nominal Scale Data. 